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Mappings

MONDO

MONDO:0014152 left ventricular noncompaction 8

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Inheritance

1

Autosomal Dominant HP:0000006

Reported PRDM16 cardiomyopathy cases follow autosomal dominant transmission of a heterozygous variant; several cases, including the fetal presentation and one of two pediatric probands in the TGF-beta mechanistic study, arose de novo.

Autosomal dominant inheritance

Show evidence (2 references)

CGGV:assertion_c0a3445a-5bb0-4d77-a4f0-5b7cfceb837f-2025-05-30T160000.000Z SUPPORT Other

ClinGen Hereditary Cardiovascular Disease GCEP records autosomal dominant inheritance for the PRDM16-dilated cardiomyopathy relationship with Strong clinical validity.

PMID:31965688 SUPPORT Human Clinical

"Exome sequencing (ES) identified a de novo unreported p.(Gln353*) heterozygous nonsense variant in PRDM16."

Documents a de novo heterozygous PRDM16 nonsense variant, consistent with autosomal dominant, often sporadic, transmission.

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Discussions and Knowledge Gaps

3

Is PRDM16-associated cardiomyopathy best classified as a form of left ventricular noncompaction, a form of dilated cardiomyopathy, or a single genotype that produces a phenotypic spectrum spanning both labels?

INTERPRETATION OPEN gap_lvnc8_noncompaction_vs_dcm_nosology

Attached to

pathophysiology#Failed Ventricular Compaction pathophysiology#Left Ventricular Dilation and Systolic Dysfunction

MONDO:0014152 is defined through the DCM axis ("any familial isolated dilated cardiomyopathy...caused by...PRDM16") even though its label and OMIM entry (615373) foreground noncompaction. The primary literature resolves this as a genuine spectrum rather than a labeling error: the founding report found PRDM16 mutations in both nonsyndromic LVNC and DCM cohorts, a large systematic rare-variant study found PRDM16 (with MYH7 and ACTN2) uniquely enriched in LVNC specifically among cardiomyopathy genes, a contemporary review reports that missense variants track with DCM while nonsense/frameshift variants track with LVNC, and mouse/human mechanistic work shows PRDM16 loss produces both noncompaction (failure of compact-myocardium specification) and LV dilation (impaired cardiomyocyte proliferation and TGF-beta-driven remodeling) from the same lesion. This dismech entry curates LVNC8 as its own genotype-defined node distinct from the polygenic LVNC umbrella entry, modeling both the noncompaction and the dilation/heart-failure branches as parallel downstream consequences of the same PRDM16 lesion rather than picking one label over the other.

Show evidence (3 references)

PMID:23768516 SUPPORT Human Clinical

"In conclusion, mutation of PRDM16 causes the cardiomyopathy in 1p36 deletion syndrome as well as a proportion of nonsyndromic LVNC and DCM."

The founding genetic report establishes PRDM16 as causal for both LVNC and DCM cohorts, directly supporting a shared-genotype spectrum rather than two separate diseases.

PMID:33500567 SUPPORT Human Clinical

"In contrast, truncating variants in MYH7, ACTN2, and PRDM16 were uniquely associated with LVNC and may reflect a distinct LVNC etiology."

A large systematic rare-variant study specifically flags PRDM16 as one of few genes with LVNC-specific (rather than shared DCM/HCM) enrichment, supporting genuine noncompaction biology alongside the DCM framing.

PMID:39337275 SUPPORT Human Clinical

"Missense variants in PRDM16 were primarily associated with DCM, whereas nonsense and frameshift mutations were associated with LVNC"

A contemporary narrative review reports a variant-class-specific genotype-phenotype correlation (missense to DCM, nonsense/frameshift to LVNC) that directly explains why the same gene produces both labeled phenotypes rather than one being a misclassification of the other.

Does loss of PRDM16 raise or lower TGF-beta signaling in the myocardium, and which direction operates in human LVNC8?

HUMAN MODEL MISMATCH OPEN gap_lvnc8_tgfbeta_direction_conflict

Attached to

pathophysiology#TGF-beta Signaling Dysregulation pathophysiology#Impaired Cardiomyocyte Proliferation

The mechanistic premise is that PRDM16 represses TGFB transcription, so losing it should de-repress the pathway. A cardiac-specific Prdm16 null mouse shows exactly that: raised Tgfb1-3 transcripts and increased phospho-Smad2. The heterozygous Prdm16Q187X knock-in, which is the genotype-matched model for a human LVNC8 patient, instead shows an age-dependent loss of TGF-beta expression. Human patient-derived iPSC-cardiomyocytes sit on the activation side, since their proliferative deficit is attributed to abnormal activation of TGF-beta signalling. The models differ in allele class (complete cardiac null versus heterozygous nonsense), dose, Cre driver, and the age at which TGF-beta was measured, and no study has compared them directly. Cre driver is worth naming among these: the authors of the ventricular-identity study state that using different Cre driver strains made the phenotypic outcome of Prdm16 animal studies highly heterogeneous, and the 1p36 cohort paper reports that Myh6-Cre knockouts alone gave hypertrophy in one model and LV dilation in another. A reconciliation has in fact been proposed: the Q187X paper concludes that PRDM16 regulates TGF-beta bidirectionally in a temporally-dependent manner, which would make activation and age-dependent loss two phases of one mechanism rather than a contradiction. That proposal is this entry's leading candidate but has not been tested against the other models, so the sign at any given developmental stage in patients remains open. This matters beyond bookkeeping because TGF-beta inhibition reversed the proliferative phenotype in the iPSC system and so is the one mechanistically motivated therapeutic direction in this entry; a mistaken sign would point that intervention the wrong way. Note also that TGF-beta receptor inhibition did not reverse the conduction abnormality in the null mouse, so even where the pathway is activated it does not account for the whole phenotype.

Show evidence (5 references)

PMID:32083975 SUPPORT Model Organism

"Moreover, TGF-β signaling was activated in Prdm16-null hearts, as evidenced by increased Tgfb1-3 transcript levels and phosphorylated Smad2."

The activation arm of the conflict, measured at ligand transcript and downstream effector level in a cardiac-specific null.

PMID:38113297 SUPPORT Model Organism

"Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression."

The opposing arm of the conflict this discussion records: the genotype-matched heterozygote loses rather than gains TGF-beta expression with age. Graded SUPPORT because the discussion's claim is that the direction is unsettled, which this finding establishes rather than contradicts.

PMID:27642787 SUPPORT In Vitro

"LVNC iPSC-CMs have decreased proliferative capacity due to abnormal activation of TGF-β signalling."

Human-derived cells fall on the activation side and are the reason the question is not purely a mouse-model curiosity.

+ 2 more references

Why is PRDM16-associated cardiomyopathy more severe in females, and does the sex effect seen in 1p36 deletion carriers extend to nonsyndromic LVNC8?

KNOWLEDGE GAP OPEN gap_lvnc8_female_predominance

Attached to

pathophysiology#Left Ventricular Dilation and Systolic Dysfunction pathophysiology#Cardiac Metabolic Dysregulation

A female-predominant severity signal appears independently in two mouse lines and in patients. Monoallelic Prdm16csp1/wt mice show diminished systolic performance that is more pronounced in females, alongside sex-divergent cardiac metabolism: triacylglycerides accumulate only in male hearts, and metabolic modelling assigns reduced fatty acid utilisation to males and lower glucose utilisation to females. A separately generated cardiac-specific Prdm16 knockout shows sex differences in the incidence and severity of contractile dysfunction and fibrosis, with significantly elevated mortality in females. In the human 1p36 deletion cohort the same direction appears, 34.5% of PRDM16-deleted females developing cardiomyopathy versus 16.7% of males, though that comparison did not reach significance at the available sample size. What is missing is a mechanism connecting the sex-divergent substrate utilisation to the sex-divergent contractile outcome, and any test of the effect in nonsyndromic PRDM16 variant carriers, where every published cohort is too small to stratify by sex. Until then, sex should not be used to stratify surveillance in LVNC8.

Show evidence (3 references)

PMID:37395136 SUPPORT INDIRECT Human Clinical

"Among those PRDM16 deleted, 34.5% of females developed cardiomyopathy versus 16.7% of their male counterparts (P=0.2)."

The human sex comparison. Directness is INDIRECT because the cohort is 1p36 deletion syndrome rather than nonsyndromic LVNC8, and the difference does not reach significance, so it establishes the question rather than the answer.

PMID:37842925 SUPPORT Model Organism

"An accumulation of triacylglycerides exclusively in male Prdm16csp1/wt hearts suggests a sex-specific metabolic adaptation."

Identifies a sex-divergent metabolic difference in the monoallelic model, the candidate substrate for the sex effect and the reason this gap attaches to the metabolic node as well as the contractile one.

PMID:37395136 SUPPORT Model Organism

"female Prdm16 conditional knockout mice demonstrate significantly elevated risk of mortality (P=0.0003)"

Independent mouse replication of the female-predominant severity signal, in a different line from the metabolic study.

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Pathophysiology

11

PRDM16 Loss-of-Function Variant

Heterozygous truncating (nonsense, frameshift) or missense PRDM16 variants reduce the dose or activity of the PRDM16 zinc-finger transcription factor. Variants cluster across the gene's 17 exons and were first mapped within the terminal 1p36 deletion syndrome critical region before being confirmed as an independent cause of nonsyndromic disease. A contemporary review reports a variant-class correlation: missense variants track with DCM, while nonsense and frameshift (loss-of-function) variants track with LVNC, and PRDM16 is predicted to be highly intolerant of loss-of-function variation.

Genetic context allele_type: SNV_INDEL variant_origin: GERMLINE zygosity: HETEROZYGOUS functional_impact_category: LOSS_OF_FUNCTION

heart left ventricle UBERON:0002084

Downstream

Loss of Compact Myocardium Transcriptional Identity Reduced PRDM16 dose removes its transcriptional activation of compact-myocardial genes and repression of trabecular-myocardial genes in left ventricular cardiomyocytes.

Cardiac Metabolic Dysregulation Independent of the compact-myocardium transcriptional program, monoallelic Prdm16 loss produces early, sex-modified metabolic and oxidative-stress changes in cardiac tissue.

Show evidence (4 references)

PMID:23768516 SUPPORT Human Clinical

"Resequencing of PRDM16 in a cohort of 75 nonsyndromic individuals with LVNC detected three mutations, including one truncation mutant, one frameshift null mutation, and a single missense mutant."

Directly documents the spectrum of PRDM16 loss-of-function and missense variants identified in nonsyndromic LVNC probands.

PMID:38113297 SUPPORT Human Clinical

"We report 2 probands with loss-of-function PRDM16 variants and pediatric left ventricular noncompaction cardiomyopathy."

Confirms loss-of-function PRDM16 variants as the proximate genetic lesion in two independently ascertained pediatric probands.

PMID:39337275 SUPPORT Human Clinical

"Missense variants in PRDM16 were primarily associated with DCM, whereas nonsense and frameshift mutations were associated with LVNC"

Establishes the variant-class-specific genotype-phenotype correlation that motivates classifying this node's loss-of-function variants as the LVNC-associated lesion class.

+ 1 more reference

Loss of Compact Myocardium Transcriptional Identity

PRDM16 is a compact-myocardium-enriched transcription factor that activates a compact-myocardial gene program while repressing a trabecular-myocardial gene program, in part through cooperation with the LV-enriched transcription factors TBX5 and HAND1. In cardiomyocyte-specific Prdm16 knockout mice, compact myocardial cardiomyocytes shift from a compact transcriptional identity toward one resembling trabecular myocardium or neurons, with reduced cardiomyocyte proliferation localized to the left ventricular compact layer and interventricular septum. Independently, single-cell RNA+ATAC sequencing shows PRDM16 favors ventricular working cardiomyocyte identity specifically by opposing the master regulators of ventricular conduction and atrial fate, so its loss also derepresses a conduction-system/atrial transcriptional program.

cardiac muscle cell CL:0000746

heart left ventricle UBERON:0002084

Animal models

Prdm16 cardiomyocyte-specific knockout mouse (Prdm16cKO) Mouse recapitulates Single-cell and spatial transcriptomics in this model define the compact-to-trabecular identity shift that the node asserts, and ChIP sequencing identifies the direct PRDM16 targets responsible.

Downstream

TGF-beta Signaling Dysregulation Loss of PRDM16-mediated repression of TGF-beta pathway genes, including direct repression of the TGFB3 promoter, de-represses TGF-beta receptor signaling in cardiomyocytes.

Failed Ventricular Compaction Loss of the compact-myocardial gene program directly impairs the structural maturation of the compact ventricular wall.

Ventricular Conduction System Hyperplasia and Atrial-Fate Derepression Loss of PRDM16-mediated suppression of conduction-system and atrial-fate master regulators allows ectopic conduction-system tissue to expand within the ventricular myocardium.

Show evidence (3 references)

PMID:34915728 SUPPORT Model Organism

"PRDM16 functioned mechanistically as a compact myocardium-enriched transcription factor that activated compact myocardial genes while repressing trabecular myocardial genes in LV compact myocardium."

Mouse cardiomyocyte-specific knockout study directly establishes the dual activator/repressor transcriptional role of PRDM16 in specifying compact versus trabecular cardiomyocyte identity.

PMID:34915728 SUPPORT Model Organism

"Prdm16cKO LV compact myocardial cardiomyocytes shifted from their normal transcriptomic identity to a transcriptional signature resembling trabecular myocardial cardiomyocytes or neurons."

Documents the specific transcriptional-identity-switch consequence of PRDM16 loss in LV compact myocardium.

PMID:39304345 SUPPORT Model Organism

"PRDM16 favors ventricular working cardiomyocyte identity, by opposing the activity of master regulators of ventricular conduction and atrial fate."

Independent single-cell RNA+ATAC-sequencing study in a mouse cardiomyocyte-specific Prdm16 deletion establishes that PRDM16 actively suppresses conduction-system and atrial cell-fate programs as part of maintaining ventricular working cardiomyocyte identity.

TGF-beta Signaling Dysregulation

PRDM16 normally binds the TGFB3 promoter and represses its transcription. Loss of PRDM16 releases this repression, producing increased TGF-beta receptor signaling in cardiomyocytes. Because TGF-beta signaling has an antiproliferative effect on cardiomyocytes, its dysregulated increase reduces cardiomyocyte proliferative capacity during the developmental window when compaction normally occurs. The INCREASED modifier records the majority position, supported by the promoter-repression mechanism, by patient-derived iPSC-cardiomyocytes, and by TGF-beta activation in Prdm16-null hearts. It is not unanimous: the genotype-matched heterozygous Prdm16Q187X mouse instead loses TGF-beta expression with age, and that model is linked below as FAILS_TO_RECAPITULATE this node. The unresolved sign is tracked in discussion gap_lvnc8_tgfbeta_direction_conflict and matters because TGF-beta inhibition is the one mechanistically motivated therapeutic direction this entry identifies.

transforming growth factor beta receptor signaling pathway GO:0007179 ↑ INCREASED

Experimental models

H9c2 rat cardiomyoblast PRDM16 promoter-binding system CELL LINE PRDM16 was raised and lowered in this line and its binding at the TGFB3 promoter assayed directly, establishing the repression step this node asserts.

Animal models

Prdm16Q187X knock-in mouse Mouse fails to recapitulate Heterozygotes do show TGF-beta dysregulation, but in the opposite direction from this node: TGF-beta expression falls with age, where losing a repressor of TGFB3 predicts, and the node asserts, an increase.

Cardiac-specific Prdm16 conditional knockout mouse (conduction and fibrosis phenotype) Mouse recapitulates TGF-beta signaling is activated in Prdm16-null hearts at both ligand transcript and downstream effector level, the direction predicted by PRDM16 acting as a repressor of TGFB transcription.

Downstream

Impaired Cardiomyocyte Proliferation Increased TGF-beta receptor signaling suppresses the proliferative expansion of developing left ventricular cardiomyocytes.

Show evidence (2 references)

PMID:38113297 SUPPORT In Vitro

"Mechanistic studies were undertaken in H9c2 cardiomyoblasts to show that PRDM16 binds TGFB3 promoter and represses its transcription."

Direct biochemical evidence that PRDM16 represses TGFB3 transcription, establishing the molecular basis for TGF-beta pathway de-repression upon PRDM16 loss. H9c2 is a rat cardiomyoblast cell line, so this is cultured-cell (IN_VITRO) evidence, not a whole-animal model.

PMID:27642787 SUPPORT In Vitro

"TBX20 regulates the expression of TGF-β signalling modifiers including one known to be a genetic cause of LVNC, PRDM16, and genome editing of PRDM16 caused proliferation defects in iPSC-CMs."

Independent iPSC-cardiomyocyte genome-editing evidence that PRDM16 loss causes the same TGF-beta-linked proliferation defect seen in the PRDM16 patient-mutation studies.

Cardiac Metabolic Dysregulation

Independently of the compact-myocardium transcriptional program, monoallelic Prdm16 loss produces early metabolic dysregulation in cardiac tissue: reduced amino-acid, glycerol, glycolytic, and tricarboxylic-acid-cycle metabolites, diminished glutathione with increased inosine monophosphate (indicating oxidative stress and dysregulated energetics), and up-regulation of two novel candidate cardiac metabolic regulators, PYROXD2 and PBXIP1. The phenotype is sex-modified: cardiac dysfunction and reduced glucose utilization are more pronounced in female mice, while triacylglyceride accumulation and reduced fatty-acid utilization are male-specific.

cellular response to oxidative stress GO:0034599 ↑ INCREASED

Animal models

Prdm16csp1/wt systemic monoallelic mouse Mouse recapitulates Metabolomic profiling of cardiac tissue defines the substrate-utilization and oxidative-stress changes this node asserts, at the earliest detectable stage.

Downstream

Left Ventricular Dilation and Systolic Dysfunction Oxidative stress and dysregulated cardiac energetics contribute to diminished systolic performance independently of the compaction/TGF-beta axis.

Show evidence (3 references)

PMID:37842925 SUPPORT Model Organism

"Prdm16csp1/wt mice are viable up to 8 months, develop hypoplastic hearts, and diminished systolic performance that is more pronounced in female mice."

Establishes the sex-modified severity of the metabolic/functional cardiac phenotype in a monoallelic Prdm16 mouse model.

PMID:37842925 SUPPORT Model Organism

"Prdm16csp1/wt cardiac tissue revealed diminished glutathione (GSH) and increased inosine monophosphate (IMP) levels indicating oxidative stress and a dysregulated energetics, respectively."

Direct metabolomic evidence for oxidative stress and dysregulated cardiac energetics as an early consequence of PRDM16 loss.

PMID:37842925 SUPPORT Model Organism

"On the level of transcripts and protein expression, Prdm16csp1/wt hearts demonstrate an up-regulation of pyridine nucleotide-disulphide oxidoreductase domain 2 (Pyroxd2) and the transcriptional regulator pre-B-cell leukaemia transcription factor interacting protein 1 (Pbxip1)."

Identifies PYROXD2 and PBXIP1 as novel transcriptionally up-regulated candidate cardiac metabolic regulators downstream of PRDM16 loss.

Impaired Cardiomyocyte Proliferation

Cardiomyocytes carrying loss-of-function PRDM16 variants show reduced proliferative capacity and increased apoptosis. In induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from a PRDM16-Q187X proband, proliferation was significantly reduced and apoptosis increased, with transcriptional dysregulation of cardiac maturation genes including TGF-beta-associated transcripts; homozygous Prdm16-Q187X knock-in mice were embryonic lethal with an underdeveloped compact myocardium.

cardiac muscle cell CL:0000746

Experimental models

PRDM16-Q187X proband-derived hiPSC-cardiomyocytes IPSC DERIVED MODEL Cardiomyocytes carrying the patient's own variant show a significant proliferative deficit with increased apoptosis, in human cells.

Animal models

Zebrafish prdm16 haploinsufficiency and truncation model Zebrafish recapitulates Reduced prdm16 dose and a human truncation allele both impair cardiomyocyte proliferative capacity, the claim this node makes.

Downstream

Failed Ventricular Compaction Reduced cardiomyocyte proliferation in the developing compact myocardium limits the thickening and maturation of the compact ventricular wall.

Left Ventricular Dilation and Systolic Dysfunction Reduced cardiomyocyte number and thinner compact/interventricular septal myocardium predispose to progressive ventricular dilation and contractile dysfunction.

Show evidence (2 references)

PMID:38113297 SUPPORT In Vitro

"Induced pluripotent stem cell-derived cardiomyocytes prepared from the PRDM16-Q187X proband demonstrated a statistically significant impairment in myocyte proliferation and increased apoptosis associated with transcriptional dysregulation of genes implicated in cardiac maturation, including..."

Patient-derived iPSC-cardiomyocyte data directly demonstrate the proliferation and apoptosis defect caused by a human loss-of-function PRDM16 variant.

PMID:38113297 SUPPORT Model Organism

"Homozygous Prdm16Q187X/Q187X mice demonstrated an underdeveloped compact myocardium and were embryonically lethal. Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression."

Knock-in mouse model carrying the human PRDM16-Q187X variant confirms dose-dependent impairment of compact myocardial development.

Failed Ventricular Compaction

Loss of PRDM16-driven compact myocardial specification and reduced compact-layer cardiomyocyte proliferation leave a thick, spongy trabeculated layer with deep intertrabecular recesses overlying a thinned compacted wall, predominantly affecting the left ventricle. In cardiomyocyte-specific Prdm16 knockout mice this produces biventricular noncompaction with LV-specific thinning of the compact myocardium and interventricular septum detectable from embryonic day 15.5.

cardiac ventricle morphogenesis GO:0003208

heart left ventricle UBERON:0002084

Animal models

Prdm16 cardiomyocyte-specific knockout mouse (Prdm16cKO) Mouse recapitulates The model develops biventricular noncompaction, the structural lesion this node names.

Prdm16Q187X knock-in mouse Mouse recapitulates Homozygous Q187X animals fail to develop a normal compact myocardium, tying the human nonsense allele directly to the compaction defect.

Downstream

Left Ventricular Dilation and Systolic Dysfunction The structurally abnormal, thinned compact wall is predisposed to progressive dilation and reduced contractile function.

Show evidence (2 references)

PMID:34915728 SUPPORT Model Organism

"Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific dilation and dysfunction, as well as biventricular noncompaction, which fully recapitulated LVNC in patients."

Mouse model directly recapitulates the human noncompaction phenotype following cardiomyocyte-specific PRDM16 loss.

PMID:31965688 SUPPORT Human Clinical

"Endocardial fibroelastosis was associated with non-compaction of the myocardium of the left ventricle."

Human fetal pathology report documents left ventricular non-compaction as the structural cardiac lesion in a de novo PRDM16 nonsense variant.

Ventricular Conduction System Hyperplasia and Atrial-Fate Derepression

PRDM16 loss removes its suppression of master regulators of ventricular conduction and atrial cell fate within ventricular working cardiomyocytes. In cardiomyocyte-specific Prdm16-deletion mice this produces hyperplasia of the distal ventricular conduction system and abnormal postnatal electrophysiology, providing a mechanistic node upstream of arrhythmia and pre-excitation phenotypes that is distinct from (and additional to) arrhythmia risk driven by ventricular dilation and remodeling.

cardiac conduction system development GO:0003161

central cardiac conduction system UBERON:2005074

Animal models

Prdm16 cardiomyocyte-specific deletion mouse (conduction-system phenotype) Mouse recapitulates Developmental myocardial Prdm16 loss expands the distal ventricular conduction system, the structural change this node asserts.

Downstream

Arrhythmia and Ventricular Pre-excitation Ectopic/hyperplastic conduction-system tissue provides a structural substrate for accessory-pathway-type pre-excitation and other rhythm disturbances.

Show evidence (2 references)

PMID:39304345 SUPPORT Model Organism

"Myocardial loss of PRDM16 during development resulted in hyperplasia of the (distal) ventricular conduction system."

Direct histological/molecular evidence that PRDM16 loss during cardiac development produces conduction-system hyperplasia, the structural substrate for a PRDM16-linked arrhythmia mechanism.

PMID:39304345 SUPPORT Model Organism

"cardiomyocyte-specific deletion of Prdm16 during cardiac development results in contractile dysfunction and abnormal electrophysiology of the postnatal heart, resulting in premature death"

Confirms that cardiomyocyte-specific PRDM16 loss produces abnormal electrophysiology in vivo, consistent with an arrhythmogenic mechanism independent of remodeling-driven arrhythmia.

Left Ventricular Dilation and Systolic Dysfunction

A subset of PRDM16 carriers develop left ventricular dilation and reduced systolic function, either accompanying noncompaction or, in some pedigrees and cardiac biopsy cohorts, as an apparently isolated dilated cardiomyopathy phenotype without prominent trabeculation, consistent with the MONDO definition of LVNC8 as a PRDM16-caused form of familial isolated dilated cardiomyopathy. Corresponds to the dismech-level phenotypes "Left Ventricular Noncompaction" and "Dilated Cardiomyopathy".

Animal models

Prdm16 cardiomyocyte-specific knockout mouse (Prdm16cKO) Mouse recapitulates The model reproduces the left-ventricle-selective dilation and systolic dysfunction that distinguishes this disease from a generic cardiomyopathy, and was generated specifically because earlier conditional lines did not.

Prdm16Q187X knock-in mouse Mouse fails to recapitulate The heterozygous state matching the human genotype produces smaller ventricular dimensions, the opposite of the ventricular dilation seen in patients carrying this class of variant.

Prdm16csp1/wt systemic monoallelic mouse Mouse partially recapitulates Systolic performance is reduced, matching the human phenotype, but the hearts are hypoplastic rather than dilated.

Zebrafish prdm16 haploinsufficiency and truncation model Zebrafish partially recapitulates Contractile dysfunction is reproduced; ventricular dilation is not assessable in this organism.

Sex-stratified cardiac-specific Prdm16 conditional knockout mouse Mouse partially recapitulates Contractile dysfunction and fibrosis develop with an incidence and severity that differ by sex, more severe in females, and female animals carry significantly elevated mortality.

Downstream

Congestive Heart Failure Progressive ventricular dilation and systolic dysfunction lead to symptomatic heart failure.

Thromboembolic Risk Blood stasis in a dilated, hypokinetic, structurally abnormal ventricle predisposes to intracardiac thrombus formation and embolism.

Arrhythmia and Ventricular Pre-excitation Ventricular dilation and remodeling independently increase arrhythmogenic risk, in addition to the conduction-system substrate described above.

Show evidence (2 references)

PMID:23768516 SUPPORT Human Clinical

"In addition, in a series of cardiac biopsies from 131 individuals with DCM, we found 5 individuals with 4 previously unreported nonsynonymous variants in the coding region of PRDM16."

Documents PRDM16 variants identified directly in a dilated cardiomyopathy biopsy cohort, supporting the DCM branch of the phenotype.

PMID:34915728 SUPPORT Model Organism

"we also observed dramatic dilation that occurred only in LV of Prdm16cKO mice"

Mouse model shows LV-specific dilation is a direct consequence of cardiomyocyte PRDM16 loss, independent of noncompaction.

Congestive Heart Failure

Affected individuals progress to congestive heart failure, often with early or infant onset in the more severe pediatric cases. A single-center pediatric LVNC cohort documented heart failure as an adverse outcome in a PRDM16-positive patient.

Show evidence (3 references)

PMID:38113297 SUPPORT Human Clinical

"One proband hosts a PRDM16-Q187X variant with left ventricular noncompaction cardiomyopathy and demonstrated infant-onset heart failure, which was selected for further study."

Documents infant-onset heart failure as a clinical outcome directly linked to a PRDM16 loss-of-function variant.

PMID:35893073 SUPPORT Human Clinical

"Among those who developed symptoms of HF (LVEF reduction and LV enlargement) were patients P9 (novel pathogenic PRDM16 complex rearrangement c.1286_1289delinsTTGCACTT p.(Gly429Valfs*176))"

A pediatric LVNC cohort documents heart failure as an adverse outcome in a PRDM16-positive patient.

PMID:31959004 SUPPORT INDIRECT Human Clinical

"The incidence rates of all-cause mortality, stroke and systemic emboli, heart failure admission, cardiac transplantation, ventricular arrhythmias, and cardiac device implantation were 2.16, 1.54, 3.53, 1.24, 2.17, and 2.66, respectively, per 100 person-years."

Gives the pooled rate of heart failure admission in LVNC, 3.53 per 100 person-years and the highest of the six event rates reported, which sizes this node against the other downstream consequences. Directness is INDIRECT because the pooled cohorts are LVNC of all causes rather than PRDM16 carriers.

Arrhythmia and Ventricular Pre-excitation

PRDM16-associated cardiomyopathy carries an increased risk of cardiac arrhythmia. Beyond the remodeling-driven arrhythmia risk shared with other dilated/noncompaction cardiomyopathies, one reported adolescent carrier presented with Wolff-Parkinson-White syndrome (ventricular pre-excitation via a complex accessory pathway), mechanistically consistent with the conduction-system-hyperplasia node above.

Animal models

Prdm16 cardiomyocyte-specific deletion mouse (conduction-system phenotype) Mouse partially recapitulates The model develops abnormal postnatal electrophysiology and premature death, giving an in vivo arrhythmic phenotype downstream of the conduction-system expansion.

Cardiac-specific Prdm16 conditional knockout mouse (conduction and fibrosis phenotype) Mouse partially recapitulates Prdm16-null hearts show measurable conduction and repolarization abnormalities (prolonged QRS and QTc) alongside dysregulated ion channel transcripts, giving a TGF-beta-independent substrate for the arrhythmia node.

Show evidence (2 references)

PMID:39895316 SUPPORT Human Clinical

"We report a 17-year-old girl with Wolff – Parkinson– White syndrome and left ventricular non-compaction cardiomyopathy due to a rare genetic variant in PR-domain containing protein 16."

Case report documents ventricular pre-excitation (Wolff-Parkinson-White syndrome) co-occurring with LVNC in a PRDM16 variant carrier.

PMID:31959004 SUPPORT INDIRECT Human Clinical

"The incidence rates of all-cause mortality, stroke and systemic emboli, heart failure admission, cardiac transplantation, ventricular arrhythmias, and cardiac device implantation were 2.16, 1.54, 3.53, 1.24, 2.17, and 2.66, respectively, per 100 person-years."

Gives the pooled ventricular arrhythmia rate in LVNC, 2.17 per 100 person-years, alongside a cardiac device implantation rate of 2.66. Directness is INDIRECT: the pooled cohorts are LVNC of all causes, and the meta-analysis reports ventricular arrhythmia generally rather than the accessory-pathway pre-excitation that also names this node.

Thromboembolic Risk

Thromboembolic complications, consistent with stasis in a dilated, hypokinetic, and structurally abnormal ventricle, have been documented in PRDM16-positive patients. A single-center pediatric LVNC cohort found two PRDM16-positive patients experienced adverse events (heart failure in one, a thromboembolic event in the other).

Show evidence (2 references)

PMID:35893073 SUPPORT Human Clinical

"A thromboembolic event, without increasing symptoms of HF, was noted in P8 (novel PRDM16 pathogenic c.1336G>T p.(Glu446*) variant)"

Documents a thromboembolic event as an adverse clinical outcome in a pediatric patient with a novel pathogenic PRDM16 variant.

PMID:31959004 SUPPORT INDIRECT Human Clinical

"The incidence rates of all-cause mortality, stroke and systemic emboli, heart failure admission, cardiac transplantation, ventricular arrhythmias, and cardiac device implantation were 2.16, 1.54, 3.53, 1.24, 2.17, and 2.66, respectively, per 100 person-years."

Gives the pooled rate of stroke and systemic emboli in LVNC, 1.54 per 100 person-years. Directness is INDIRECT because the pooled cohorts are LVNC of all causes rather than PRDM16 carriers.

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Pathograph

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Phenotypes

7

Blood 1

Thromboembolic Event Thromboembolism HP:0001907

Show evidence (1 reference)

PMID:35893073 SUPPORT Human Clinical

"A thromboembolic event, without increasing symptoms of HF, was noted in P8 (novel PRDM16 pathogenic c.1336G>T p.(Glu446*) variant)"

Documents a thromboembolic event as an adverse clinical outcome in a pediatric patient with a novel pathogenic PRDM16 variant.

Cardiovascular 5

Left Ventricular Noncompaction HP:0030682

Show evidence (1 reference)

PMID:23768516 SUPPORT Human Clinical

"Resequencing of PRDM16 in a cohort of 75 nonsyndromic individuals with LVNC detected three mutations, including one truncation mutant, one frameshift null mutation, and a single missense mutant."

Establishes left ventricular noncompaction as a clinical phenotype directly associated with PRDM16 variants.

Dilated Cardiomyopathy HP:0001644

Show evidence (1 reference)

PMID:23768516 SUPPORT Human Clinical

"In addition, in a series of cardiac biopsies from 131 individuals with DCM, we found 5 individuals with 4 previously unreported nonsynonymous variants in the coding region of PRDM16."

Documents dilated cardiomyopathy as a clinical phenotype directly associated with PRDM16 variants, independent of a noncompaction diagnosis.

Congestive Heart Failure FREQUENT HP:0001635

Show evidence (1 reference)

PMID:38113297 SUPPORT Human Clinical

"One proband hosts a PRDM16-Q187X variant with left ventricular noncompaction cardiomyopathy and demonstrated infant-onset heart failure, which was selected for further study."

Confirms heart failure, with infant onset in the severe pediatric case reported, as a clinical feature of PRDM16-associated cardiomyopathy.

Wolff-Parkinson-White Syndrome HP:0001716

Show evidence (1 reference)

PMID:39895316 SUPPORT Human Clinical

"We report a 17-year-old girl with Wolff – Parkinson– White syndrome and left ventricular non-compaction cardiomyopathy due to a rare genetic variant in PR-domain containing protein 16."

Case report documents Wolff-Parkinson-White syndrome co-occurring with LVNC in a PRDM16 variant carrier.

Myocardial Fibrosis HP:0001685

Show evidence (1 reference)

PMID:38113297 SUPPORT Model Organism

"Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression."

Documents heightened myocardial fibrosis as a feature of the heterozygous PRDM16-Q187X mouse model.

Metabolism 1

Fetal-Onset Cardiomegaly and Hydrops VERY_RARE Nonimmune hydrops fetalis HP:0001790

Show evidence (1 reference)

PMID:31965688 SUPPORT Human Clinical

"The third-trimester obstetric ultrasound revealed a hydropic fetus with hydramnios and expanded hypokinetic heart. After termination of pregnancy, foetopathology showed a eutrophic fetus with isolated cardiomegaly."

First reported fetal presentation of PRDM16-associated cardiomyopathy, establishing hydrops fetalis and cardiomegaly as a rare but documented severe end of the phenotypic spectrum.

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Genetic Associations

1

PRDM16 (Pathogenic Variants)

Gene: PRDM16 hgnc:14000 gene page

Show evidence (2 references)

PMID:23768516 SUPPORT Human Clinical

"PRDM16 has not previously been associated with cardiac disease but is localized in the nuclei of cardiomyocytes throughout murine and human development and in the adult heart."

Establishes PRDM16 as the founding causal gene for this entity and documents its cardiomyocyte nuclear localization.

CGGV:assertion_c0a3445a-5bb0-4d77-a4f0-5b7cfceb837f-2025-05-30T160000.000Z SUPPORT Other

ClinGen classifies the PRDM16-dilated cardiomyopathy gene-disease relationship as strong with autosomal dominant inheritance.

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Medical Actions

5

Guideline-Directed Heart Failure Pharmacotherapy

Action: Pharmacotherapy NCIT:C15986

Platform: Small molecule

Standard heart failure pharmacotherapy (e.g., ACE inhibitors/ARBs or ARNI, beta-blockers, mineralocorticoid receptor antagonists, SGLT2 inhibitors) is used to manage systolic dysfunction in PRDM16-associated cardiomyopathy. There is no PRDM16- or LVNC8-specific pharmacotherapy; management follows the general phenotype-based approach used for LVNC and DCM.

Show evidence (1 reference)

PMID:25443708 SUPPORT Other

"Currently, there are no specific treatments for LVNC. Depending on the phenotype, patients are managed according to their clinical needs and corresponding guidelines (e.g., for congestive heart failure, arrhythmias)."

States directly that LVNC (and by extension LVNC8) has no disease-specific pharmacotherapy and is managed with standard phenotype-based guideline therapy. Evidence source is OTHER because this is a review.

Implantable Cardioverter-Defibrillator Placement

Action: Implantable Cardioverter-Defibrillator Placement NCIT:C80435

Platform: Device

ICD implantation is considered for PRDM16-associated cardiomyopathy patients at risk of ventricular arrhythmia and sudden cardiac death, following conventional primary/secondary-prevention criteria for LVNC/DCM rather than a PRDM16-specific indication.

Show evidence (1 reference)

PMID:25443708 SUPPORT Human Clinical

"In 30 patients with LVNC who underwent implantable cardioverter defibrillator (ICD) implantation for secondary or primary prevention, 11 patients (37%) had appropriate ICD therapies in a mean follow-up period of 40 ± 34 months"

Reports outcome data for ICD implantation specifically in LVNC patients (37% received appropriate therapy), directly supporting ICD placement as a real intervention with documented efficacy signal in this cardiomyopathy.

Anticoagulation for Thromboembolic Risk

Action: Pharmacotherapy NCIT:C15986

Agent: anticoagulant agent NCIT:C263

Platform: Small molecule

Anticoagulant therapy is considered in patients with reduced systolic function or documented thromboembolic events, given the thromboembolic complications reported in PRDM16-positive LVNC patients. Routine anticoagulation for isolated trabeculation with normal ventricular function remains debated.

Show evidence (2 references)

PMID:25443708 SUPPORT Other

"Oral anticoagulation is a debated issue in subjects with normal LV function and absence of LV hypertrophy: patients are either treated on the basis of the phenotype (oral anticoagulation given independently on arrhythmias or LV dysfunction for primary prevention of embolic episodes) or in the..."

States the clinical indications for oral anticoagulation in LVNC directly. Evidence source is OTHER because this is a review.

PMID:35893073 SUPPORT Human Clinical

"A thromboembolic event, without increasing symptoms of HF, was noted in P8 (novel PRDM16 pathogenic c.1336G>T p.(Glu446*) variant)"

Documents a thromboembolic complication in a PRDM16-positive patient, the clinical indication anticoagulation is intended to prevent.

Cardiac Transplantation

Action: Organ Transplantation NCIT:C15289

Platform: Surgery

Heart transplantation is the definitive treatment for end-stage heart failure in severe PRDM16-associated cardiomyopathy, following standard advanced-heart-failure criteria rather than a PRDM16-specific one. A multi-institutional 1p36 deletion cohort does show that PRDM16 deletion carries an increased risk of a combined endpoint of death, transplant or ventricular assist device, so the genotype does bear on how often this endpoint is reached; that cohort is the contiguous-gene-deletion context rather than nonsyndromic LVNC8. Rates at the level of LVNC as a whole are recorded alongside.

Show evidence (3 references)

PMID:35893073 SUPPORT INDIRECT Human Clinical

"Mechanical circulatory support (LVAD) was implanted in a patient with extremely low LV systolic function; he was qualified for heart transplant, but died while waiting for a heart transplant."

Documents escalation to mechanical circulatory support and transplant candidacy as the real endpoint of end-stage systolic failure in a paediatric LVNC cohort. Directness is INDIRECT because the transplant candidate in this series is not one of its two PRDM16-positive patients, so this supports transplantation as the LVNC endpoint rather than as a PRDM16-specific indication.

PMID:37395136 SUPPORT INDIRECT Human Clinical

"PRDM16 deletion was associated with increased risk of death, cardiac transplant, or ventricular assist device (P=0.04)."

Ties PRDM16 loss itself to the transplant and mechanical-support endpoint, against a within-syndrome comparison group whose deletion spares PRDM16. Directness is INDIRECT on two counts: the cohort is 1p36 deletion syndrome rather than nonsyndromic LVNC8, and the endpoint is combined with death and ventricular assist device, so it does not report a transplant rate on its own.

PMID:39420976 SUPPORT INDIRECT Human Clinical

"Mortality and heart transplantation rates were 12% and 7%, respectively."

Gives the pooled adult transplantation rate for LVNC, which sizes how often this treatment is reached. Directness is INDIRECT because the pooled cohorts are LVNC of all causes rather than PRDM16 carriers.

Cascade Genetic Testing and Counseling

Action: Genetic Counseling NCIT:C15240

Platform: Behavioral / lifestyle

Genetic testing for the proband's PRDM16 variant and cascade testing of at-risk relatives is recommended given autosomal dominant transmission, given that a subset of first-degree relatives of PRDM16 probands may carry the variant.

Show evidence (2 references)

PMID:31965688 SUPPORT Human Clinical

"Exome sequencing (ES) identified a de novo unreported p.(Gln353*) heterozygous nonsense variant in PRDM16."

Documents molecular genetic testing (exome sequencing) as the diagnostic route to identifying a causal PRDM16 variant, supporting genetic testing and counseling as a management step.

PMID:20301486 SUPPORT Other

"Provide a basic view of genetic risk assessment of at-risk asymptomatic relatives of a proband with DCM to inform cardiac surveillance and allow early detection and treatment of DCM to improve long-term outcome."

The GeneReviews DCM overview frames genetic risk assessment of at-risk asymptomatic relatives, with cardiac surveillance for early detection, as the purpose of cascade evaluation — precisely this treatment. Evidence source is OTHER because GeneReviews is an expert-authored review resource.

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Diagnosis

4

Echocardiography

First-line imaging modality for LVNC. The most widely used echocardiographic diagnostic criterion is a noncompacted-to-compacted (NC/C) myocardial thickness ratio greater than 2.0 measured at end-systole, though this threshold carries substantial interobserver and intraobserver variability and is not LVNC8-specific.

echocardiography NCIT:C16525

Show evidence (1 reference)

PMID:25443708 SUPPORT Other

"the most important echocardiographic criterion remains the ratio of noncompacted/compacted >2.0 in end-systole"

States the quantitative echocardiographic NC/C >2.0 criterion used to diagnose LVNC. Evidence source is OTHER because this is a review.

Cardiac Magnetic Resonance Imaging

CMR gives a 3-dimensional dataset that better resolves trabecular architecture than echocardiography. A noncompacted-to-compacted ratio greater than 2.3 measured at end-diastole on CMR is the commonly cited diagnostic cutoff, and CMR additionally assesses fibrosis via late gadolinium enhancement. Neither the echocardiographic nor the CMR threshold is sufficiently specific in isolation.

cardiac magnetic resonance imaging NCIT:C16809

Show evidence (1 reference)

PMID:25443708 SUPPORT Other

"A noncompacted/compacted ratio >2.3 on CMR is considered the cutoff for LVNC diagnosis"

States the quantitative CMR NC/C >2.3 criterion used to diagnose LVNC. Evidence source is OTHER because this is a review.

Natriuretic Peptide Measurement

BNP/NT-proBNP assesses heart failure severity and cardiomyocyte stretch but is not diagnostic of LVNC8 specifically. Heterozygous Prdm16 mutant mice show elevated plasma BNP, supporting its use as a marker of cardiac stretch/dysfunction downstream of PRDM16 loss rather than a disease-specific biomarker.

brain natriuretic peptide measurement NCIT:C74735

Show evidence (1 reference)

PMID:37842925 SUPPORT Model Organism

"We found an elevation of plasma levels of brain natriuretic peptide (Bnp) in both sexes, indicating cardiomyocyte stretch with impaired systolic and possibly diastolic LV dysfunction"

Mouse-model evidence that BNP is elevated downstream of PRDM16 loss; PARTIAL because this is a general heart-failure-stretch biomarker in a mouse model, not an LVNC8-specific human diagnostic marker.

Cardiomyopathy Multigene Panel Sequencing with Copy-Number Analysis

The confirmatory test is a clinically curated cardiomyopathy gene panel including PRDM16. Copy-number analysis (chromosomal microarray) is important alongside sequencing specifically to distinguish an intragenic PRDM16 variant (LVNC8) from a 1p36 deletion spanning PRDM16 (1p36 deletion syndrome), since the original mapping of the PRDM16 cardiac critical region was itself done by comparative genomic hybridization delineating the terminal 1p36 deletion interval.

cardiomyopathy multigene panel sequencing with copy-number analysis NCIT:C15709

Show evidence (2 references)

PMID:20301486 SUPPORT Other

"Provide the evaluation strategy of a proband with nonsyndromic DCM"

The GeneReviews DCM overview exists to supply this proband evaluation strategy, of which gene-panel and copy-number testing is a component. Evidence source is OTHER because GeneReviews is an expert-authored review resource.

PMID:23768516 SUPPORT Human Clinical

"we identified a minimal deletion for the cardiomyopathy associated with 1p36del syndrome that included only the terminal 14 exons of the transcription factor PRDM16"

Comparative genomic hybridization (the copy-number method) was how the PRDM16 cardiac critical region within the 1p36 deletion was originally delineated, supporting copy-number analysis as the tool that distinguishes a 1p36 deletion from an intragenic PRDM16 variant.

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Prevalence

1

Molecularly confirmed PRDM16-associated LVNC (LVNC8)

Unknown Not yet documented

No prevalence or incidence estimate exists for molecularly confirmed LVNC8, so no band or rate is asserted for this entity. Two published figures bound it from either side and are recorded here with their evidence rather than as structured rates, because neither has LVNC8 as its denominator and a structured band would misreport this rare Mendelian entity. Upper bound: pooled adult prevalence of the LVNC phenotype from all causes is 0.5%, of which PRDM16 explains only a fraction; the same review reports a 1.3% detection rate by cardiovascular magnetic resonance, which is a modality effect rather than a second estimate and shows how strongly LVNC ascertainment depends on imaging method and criteria. Penetrance, not prevalence: among 134 individuals with 1p36 deletion syndrome, 29.1% of those whose deletion removed PRDM16 developed cardiomyopathy against 10.8% of those whose deletion spared it; the retrospective arm alone (n=71) gave 34.5% versus 7.7% without reaching significance. That is the contiguous-gene-deletion context and other genes in the interval may modify the risk, so it is not the penetrance of a nonsyndromic PRDM16 variant.

Show evidence (3 references)

PMID:39420976 SUPPORT INDIRECT Human Clinical

"The study showed a prevalence of LVNC of 0.5%, with cardiovascular magnetic resonance outperforming echocardiography in diagnosis with a detection rate of 1.3%."

Supplies the upper bound recorded above. Directness is INDIRECT because the pooled denominator is adults screened for the LVNC phenotype from all causes, not PRDM16 carriers, so it bounds LVNC8 without estimating it.

PMID:37395136 SUPPORT INDIRECT Human Clinical

"In the combined retrospective and systematic review cohort (n=134), PRDM16 deletion-associated cardiomyopathy risk was recapitulated and significant (29.1% versus 10.8%, P=0.03)."

Supplies the penetrance figure recorded above, isolating PRDM16's contribution against a within-syndrome comparison group whose deletion spares the gene. Directness is INDIRECT because the cohort is 1p36 deletion syndrome rather than nonsyndromic LVNC8, and because cardiomyopathy incidence in an at-risk genotype is penetrance, not the population prevalence this slot otherwise reports.

PMID:37395136 SUPPORT INDIRECT Human Clinical

"Among individuals with PRDM16 deleted, 34.5% developed cardiomyopathy versus 7.7% of individuals with PRDM16 not deleted (P=0.1)."

The retrospective arm considered alone, recorded because its effect size is larger than the pooled figure while its P value does not reach significance at this sample size. Directness is INDIRECT for the same reasons as the pooled figure above.

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Differential Diagnoses

2

Conditions with similar clinical presentations that must be differentiated from Left Ventricular Noncompaction 8:

Left ventricular noncompaction (polygenic umbrella) MONDO:0018901

Overlapping Features Isolated LVNC of other or undetermined genetic cause, including sarcomeric (MYH7, ACTN2), cytoskeletal (NRAP), and mitochondrial (TAFAZZIN) etiologies modeled in the umbrella dismech entry.

Distinguishing Features

A confirmed PRDM16 loss-of-function variant identifies LVNC8 specifically, versus the broader genetically heterogeneous LVNC umbrella.
Truncating PRDM16 (along with MYH7 and ACTN2) variants show LVNC-specific enrichment in large rare-variant studies, unlike genes shared broadly across DCM/HCM/LVNC.

Show evidence (1 reference)

PMID:33500567 SUPPORT Human Clinical

"In contrast, truncating variants in MYH7, ACTN2, and PRDM16 were uniquely associated with LVNC and may reflect a distinct LVNC etiology."

Directly distinguishes PRDM16 (and MYH7/ACTN2) from the broader, LVNC-associated gene set as having LVNC-specific rare-variant enrichment.

1p36 deletion syndrome

Overlapping Features A contiguous-gene deletion syndrome of the terminal short arm of chromosome 1 that includes PRDM16 within its cardiomyopathy critical region, together with craniofacial anomalies, intellectual disability, seizures, and other syndromic features not present in isolated LVNC8.

Distinguishing Features

1p36 deletion syndrome is a multigene contiguous deletion with extracardiac syndromic features; LVNC8 is a nonsyndromic, single-gene PRDM16 point-mutation or small-indel disorder confined to the cardiac phenotype.
Array CGH or chromosomal microarray identifying a terminal 1p36 deletion spanning PRDM16 (rather than an intragenic PRDM16 variant) indicates 1p36 deletion syndrome rather than LVNC8.

Show evidence (1 reference)

PMID:23768516 SUPPORT Human Clinical

"we identified a minimal deletion for the cardiomyopathy associated with 1p36del syndrome that included only the terminal 14 exons of the transcription factor PRDM16"

Establishes PRDM16 as the cardiomyopathy-critical gene within the larger 1p36 deletion syndrome region, distinguishing the contiguous-gene syndrome from isolated PRDM16 point-mutation disease.

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Related Datasets

1

PRDM16 Modulates Aspects of Cell-Cycle Dynamics and Maturation in Human iPSC-Derived Cardiomyocytes geo:GSE307782

human BULK RNA SEQ

siRNA knockdown and lentiviral overexpression of PRDM16 in hiPSC-derived cardiomyocytes, directly probing the proliferation-maturation axis implicated in the PRDM16 loss-of-function mechanism curated above (reduced PRDM16 impairs metabolic/structural maturation and sarcomeric protein ratios; no linked PMID at time of curation).

Show evidence (1 reference)

GEO:GSE307782 SUPPORT In Vitro

"Reduced PRDM16 expression significantly impairs the metabolic and structural maturation of hiPSC-CMs, leading to dysregulated sarcomeric protein expression ratios and compromised engineered heart tissue (EHT) function."

The repository's own summary states what the deposited experiment shows: lowering PRDM16 in human cardiomyocytes impairs maturation and contractile tissue function, which is the human-cell counterpart of the proliferation and maturation arm of the mechanism curated above.

🔬

Clinical Trials

2

NCT06024759 NOT_APPLICABLE RECRUITING

Ten-year observational registry following patients with left ventricular noncompaction to identify predictors of adverse outcome. Its stated questions map onto this entry's downstream nodes almost directly: whether genotype predicts ventricular arrhythmia risk, what determines left ventricular dysfunction in LVNC, and which rhythm markers predict ICD implantation. Not PRDM16-specific, but it is the study most likely to produce genotype-stratified arrhythmia risk for genes including PRDM16. Phase is NOT_APPLICABLE because this is an observational registry rather than an interventional trial.

Target Phenotypes: Ventricular arrhythmia HP:0004308 Left ventricular noncompaction HP:0030682

Show evidence (1 reference)

clinicaltrials:NCT06024759 SUPPORT Human Clinical

"Are there any genetic mutations that impact the risk of LVNC patients developing ventricular arrhythmias?"

The registry's primary question is whether genotype stratifies arrhythmia risk in LVNC, which is the open question this entry's arrhythmia node leaves for PRDM16 carriers.

NCT03572569 NOT_APPLICABLE UNKNOWN

RIKADA, a prospective family-based study of children and adolescents with primary cardiomyopathy, screening probands and first-degree relatives clinically and genetically to support risk stratification. Relevant here as the paediatric counterpart of the cascade-testing treatment curated in this entry, though it covers primary cardiomyopathy broadly rather than LVNC or PRDM16 specifically. Registry status is UNKNOWN as of this curation, with recruiting the last reported state; phase is NOT_APPLICABLE because it is observational.

Show evidence (1 reference)

clinicaltrials:NCT03572569 SUPPORT INDIRECT Human Clinical

"RIKADA is a prospective study performing systematic family screening including clinical and genetic testing in pediatric patients with primary cardiomyopathy and their first-degree relatives with the aim to facilitate risk stratification."

Describes systematic family screening with genetic testing in paediatric cardiomyopathy, the practice this entry curates as cascade testing. Directness is INDIRECT because the study population is primary cardiomyopathy generally, not LVNC or PRDM16 carriers.

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Experimental Models

2

PRDM16-Q187X proband-derived hiPSC-cardiomyocytes IPSC_DERIVED_MODEL

Cardiomyocytes differentiated from induced pluripotent stem cells of the proband carrying the PRDM16 Q187X nonsense variant. This is the only human system in this entry that carries an actual LVNC8 genotype, which is what makes it the strongest available test of whether the proliferative arm of the mechanism operates in human cells rather than only in mouse and zebrafish. It was phenotyped alongside the Q187X knock-in mouse in the same study.

Organism

human NCBITaxon:9606

Cell source

patient-derived iPSC

Culture

monolayer hiPSC-cardiomyocyte culture

Publication

PMID:38113297

Pathograph links

Impaired Cardiomyocyte Proliferation recapitulates fidelity: high observes: cellular Cardiomyocytes carrying the patient's own variant show a significant proliferative deficit with increased apoptosis, in human cells.

Limitations: hiPSC-cardiomyocytes are fetal-like and proliferation-competent, unlike adult human cardiomyocytes, so the deficit is measured against a developmental baseline that has no adult counterpart. The system is also derived from a single proband, so genetic background is not controlled.

Readouts

Cardiomyocyte proliferation and apoptosis

Proliferative and apoptotic indices in Q187X proband hiPSC-CMs versus control.

Direction: DECREASED

Interpretation: Reduced proliferation with increased apoptosis is the cellular deficit this node names, measured here in human cells.

Show evidence (1 reference)

PMID:38113297 SUPPORT In Vitro

"Induced pluripotent stem cell-derived cardiomyocytes prepared from the PRDM16-Q187X proband demonstrated a statistically significant impairment in myocyte proliferation and increased apoptosis associated with transcriptional dysregulation of genes implicated in cardiac maturation, including..."

Reports both measurements and their direction in the genotype-matched human system.

Show evidence (1 reference)

PMID:38113297 SUPPORT In Vitro

"Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from Proband 1 and Prdm16-Q187X knock in mouse model, we demonstrate that PRDM16 regulates proliferation of cardiomyocytes in humans and mice."

Attests that this system is informative for the proliferation node specifically, and that the human and mouse arms agree on it, which is what the node's cross-species claim rests on.

Show evidence (1 reference)

PMID:38113297 SUPPORT In Vitro

"Induced pluripotent stem cell-derived cardiomyocytes were generated from a proband hosting a Q187X nonsense variant as an in vitro model and underwent proliferative and transcriptional analyses."

Establishes the system's provenance from a genotyped LVNC8 proband and the analyses it underwent.

H9c2 rat cardiomyoblast PRDM16 promoter-binding system CELL_LINE

The immortalized rat cardiomyoblast line used for the loss- and gain-of-function and ChIP-PCR work that establishes PRDM16 binding at the TGFB3 promoter. It is a mechanistic reduction rather than a disease model: it carries no LVNC8 genotype and models no clinical phenotype, but it is where the repression step underlying the TGF-beta node was demonstrated.

Organism

Norway rat NCBITaxon:10116

Cell source

immortalized rat cardiomyoblast line

Culture

monolayer cell culture with adenoviral expression

Publication

PMID:38113297

Pathograph links

TGF-beta Signaling Dysregulation perturbs fidelity: low observes: molecular PRDM16 was raised and lowered in this line and its binding at the TGFB3 promoter assayed directly, establishing the repression step this node asserts.

Limitations: A rat immortalized cardiomyoblast line is neither human nor a cardiomyocyte, carries no LVNC8 variant, and expresses PRDM16 from an adenoviral construct rather than at endogenous dose. It establishes that PRDM16 can repress TGFB3, not that this repression sets the direction of TGF-beta signaling in patient myocardium; the conflicting in vivo directions recorded elsewhere in this entry are exactly why that distinction matters.

Readouts

PRDM16 occupancy at the Tgfb3 promoter

ChIP-PCR of Myc-tagged PRDM16 with histone H3K4 methylation state at the same region.

Direction: INCREASED

Interpretation: Direct promoter occupancy, with the H3K4me1 up and H3K4me3 down shift that accompanies repression, is the molecular basis of this node.

Show evidence (1 reference)

PMID:38113297 SUPPORT In Vitro

"Using these primers, we performed ChIP-PCR of Myc-tagged PRDM16 expressed via adenovirus in H9c2 cells and confirmed binding at the Tgfb3 and Tgfb2 promoter"

Reports the occupancy measurement this readout records, at Tgfb3 and also Tgfb2.

Show evidence (1 reference)

PMID:38113297 SUPPORT In Vitro

"Mechanistic studies were undertaken in H9c2 cardiomyoblasts to show that PRDM16 binds TGFB3 promoter and represses its transcription."

Attests that this system is informative for the TGF-beta node: it is where the promoter-level repression the node is built on was demonstrated.

Show evidence (1 reference)

PMID:38113297 SUPPORT In Vitro

"we used Prdm16 loss-and-gain-of-function studies in rat cardiac H9c2 cardiomyoblasts"

Establishes the system and the bidirectional perturbation design behind the promoter-level claim.

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Animal Models

7

Prdm16 cardiomyocyte-specific knockout mouse (Prdm16cKO)

Conditional deletion of Prdm16 restricted to cardiomyocytes. Unlike earlier conditional Prdm16 lines, this model reproduces the left-ventricle-selective vulnerability seen in patients: it develops LV-specific dilation and systolic dysfunction together with biventricular noncompaction. Paired RNA sequencing, ChIP sequencing, single-cell RNA sequencing and spatial transcriptomics in the same model identify the direct transcriptional targets of PRDM16 and show that compact-layer cardiomyocytes lose their normal transcriptomic identity. It is the reference in vivo model for the compact-myocardium transcriptional arm of the LVNC8 mechanism.

Species

Mouse

Genotype

Prdm16 conditional knockout, cardiomyocyte-restricted via Xmlc2-Cre and, independently, cTnT-Cre (both lines called Prdm16cKO in the paper)

Genes

PRDM16 hgnc:14000

Publication

PMID:34915728

Pathograph links

Loss of Compact Myocardium Transcriptional Identity recapitulates fidelity: high observes: cellular Single-cell and spatial transcriptomics in this model define the compact-to-trabecular identity shift that the node asserts, and ChIP sequencing identifies the direct PRDM16 targets responsible.

Limitations: Cardiomyocyte-restricted deletion removes Prdm16 from every cardiomyocyte, whereas human LVNC8 is a germline heterozygous state with residual PRDM16 dose in all lineages, so the transcriptional shift is expected to be more complete here than in patients.

Readouts

Compact-myocardial versus trabecular transcriptional signature

Single-cell RNA sequencing with spatial transcriptomics of LV compact myocardium, scored for compact- versus trabecular-identity genes.

Direction: ALTERED

Interpretation: A compact-layer cardiomyocyte reading out as trabecular is the direct measurement behind this node.

Show evidence (1 reference)

PMID:34915728 SUPPORT Model Organism

"Consequently, Prdm16cKO LV compact myocardial cardiomyocytes shifted from their normal transcriptomic identity to a transcriptional signature resembling trabecular myocardial cardiomyocytes or neurons."

Reports the transcriptomic measurement and its direction in this model.

Show evidence (1 reference)

PMID:34915728 SUPPORT Model Organism

"PRDM16 functioned mechanistically as a compact myocardium-enriched transcription factor that activated compact myocardial genes while repressing trabecular myocardial genes in LV compact myocardium."

Attests that this model is informative for the node: the dual activator/repressor role defining compact-myocardial identity was established in this knockout, which is what licenses reading the node off this model.

Failed Ventricular Compaction recapitulates fidelity: high observes: tissue The model develops biventricular noncompaction, the structural lesion this node names.

Limitations: Noncompaction here is biventricular, whereas the human disease label and the patient phenotype foreground the left ventricle; the chamber distribution is therefore broader in the model than in patients.

Show evidence (1 reference)

PMID:34915728 SUPPORT Model Organism

"Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific dilation and dysfunction, as well as biventricular noncompaction, which fully recapitulated LVNC in patients."

States that the model reproduces the noncompaction phenotype of patients, which is the claim this link makes.

Left Ventricular Dilation and Systolic Dysfunction recapitulates fidelity: high observes: organism The model reproduces the left-ventricle-selective dilation and systolic dysfunction that distinguishes this disease from a generic cardiomyopathy, and was generated specifically because earlier conditional lines did not.

Limitations: Chamber selectivity is reproduced, and the paper offers the LV-restricted transcriptional program as its explanation, but presents that as an explanation for a subset of LVNC cardiomyopathies rather than a general one. How far it extends to PRDM16 patients specifically is untested.

Show evidence (1 reference)

PMID:34915728 SUPPORT Model Organism

"Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific dilation and dysfunction, as well as biventricular noncompaction, which fully recapitulated LVNC in patients."

Directly reports LV-specific dilation and dysfunction in the model and its correspondence to the patient phenotype.

Show evidence (2 references)

PMID:34915728 SUPPORT Model Organism

"Prdm16 cardiomyocyte-specific knockout (Prdm16cKO) mice were generated and analyzed for cardiac phenotypes."

Establishes the model's construction and that it was characterized for cardiac phenotypes, which is what makes it usable as an in vivo model of this disease.

PMID:34915728 SUPPORT Model Organism

"indicating that cardiac phenotypes we observed in Prdm16cKO mice were not Cre driver line dependent"

Names why this line is the reference model rather than one of several: the phenotype was reproduced across two independent Cre drivers, which is the control the earlier conditional lines lacked and which matters because Cre driver is a known source of divergence between Prdm16 knockout studies.

Prdm16Q187X knock-in mouse

CRISPR-mediated knock-in of the patient-derived Q187X nonsense allele, generated alongside iPSC-cardiomyocytes from the proband carrying the same variant. It is the only mouse in this entry built on a specific human LVNC8 allele rather than on gene deletion (the zebrafish model also expresses a human truncation allele), which makes it the strongest available mammalian test of allele-level causality. Homozygotes are embryonically lethal with an underdeveloped compact myocardium; heterozygotes show fibrosis and age-dependent loss of TGF-beta expression, but smaller rather than dilated ventricles.

Species

Mouse

Genotype

Prdm16Q187X knock-in (heterozygous Prdm16Q187X/WT and homozygous Prdm16Q187X/Q187X)

Genes

PRDM16 hgnc:14000

Publication

PMID:38113297

Pathograph links

Failed Ventricular Compaction recapitulates fidelity: moderate observes: tissue Homozygous Q187X animals fail to develop a normal compact myocardium, tying the human nonsense allele directly to the compaction defect.

Limitations: The compaction phenotype requires the homozygous state, which is embryonically lethal and has no human counterpart: LVNC8 patients are heterozygous. The allele's compaction effect in mice is therefore demonstrated at a dose humans never carry.

Show evidence (1 reference)

PMID:38113297 SUPPORT Model Organism

"Homozygous Prdm16Q187X/Q187X mice demonstrated an underdeveloped compact myocardium and were embryonically lethal."

Reports the compaction defect and the zygosity at which it appears.

TGF-beta Signaling Dysregulation fails to recapitulate fidelity: low observes: molecular Heterozygotes do show TGF-beta dysregulation, but in the opposite direction from this node: TGF-beta expression falls with age, where losing a repressor of TGFB3 predicts, and the node asserts, an increase.

Limitations: This is a direction mismatch on the node's asserted quantity rather than a missing measurement, which is why the link is FAILS_TO_RECAPITULATE and not PARTIALLY_RECAPITULATES: the model moves the opposite way. It also conflicts with the cardiac-specific Prdm16 null model below, where TGF-beta signaling is activated, and with the patient-derived iPSC-cardiomyocytes, whose proliferative deficit is attributed to TGF-beta activation. Allele class, dose, Cre driver and age at measurement all differ across these systems. This paper's own proposal is that PRDM16 regulates TGF-beta bidirectionally in a temporally-dependent manner, which would reconcile them; until that is tested across models this link must not be used to infer the direction of the TGF-beta change in patients at any given stage. See discussion gap_lvnc8_tgfbeta_direction_conflict.

Readouts

Myocardial TGF-beta expression

Transcriptional analysis of Prdm16Q187X/WT hearts across age.

Direction: DECREASED

Interpretation: An age-dependent fall in TGF-beta expression is the measured dysregulation in this model.

Show evidence (1 reference)

PMID:38113297 SUPPORT Model Organism

"Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression."

Reports the direction and age dependence of the TGF-beta measurement.

Show evidence (1 reference)

PMID:38113297 SUPPORT Model Organism

"Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression."

Substantiates the FAILS_TO_RECAPITULATE claim: the model does measure TGF-beta in the genotype-matched heterozygote, and the measurement falls with age where this node asserts an increase.

Left Ventricular Dilation and Systolic Dysfunction fails to recapitulate fidelity: low observes: organism The heterozygous state matching the human genotype produces smaller ventricular dimensions, the opposite of the ventricular dilation seen in patients carrying this class of variant.

Limitations: This is a substantive negative result, not a gap in phenotyping: the heterozygous Q187X mouse is the genotype-matched animal and it diverges in direction from the human phenotype on this node. Ventricular dimensions from this model must not be used to infer human chamber remodeling, and any therapeutic inference about reverse remodeling drawn from it would be inverted. Fibrosis is reproduced, so the model remains informative for the fibrotic component while failing on chamber size.

Readouts

Ventricular chamber dimensions

Echocardiographic and histological ventricular dimensions in Prdm16Q187X/WT mice versus wild-type littermates.

Direction: DECREASED

Interpretation: Decreased chamber dimension in the model against dilation in patients is the direction mismatch that makes this a failure to recapitulate.

Show evidence (1 reference)

PMID:38113297 SUPPORT Model Organism

"Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression."

Reports smaller, not larger, ventricular dimensions in the genotype-matched heterozygote.

Show evidence (1 reference)

PMID:38113297 SUPPORT Model Organism

"Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression."

Supports the FAILS_TO_RECAPITULATE claim this link makes: the genotype-matched heterozygote moves in the opposite direction on chamber size from the human phenotype this node describes, which is the failure being asserted rather than a contradiction of it.

Show evidence (1 reference)

PMID:38113297 SUPPORT Model Organism

"CRISPR (clustered regularly interspaced short palindromic repeats)-mediated knock-in mouse model hosting the Prdm16Q187X allele was generated and subjected to ECG, histological, and transcriptional analysis."

Establishes that the model carries the patient's own nonsense allele and the phenotyping it underwent.

Prdm16csp1/wt systemic monoallelic mouse

Systemic heterozygous Prdm16 inactivation, the closest genotype match in this entry to the human heterozygous state. Profiled by transcriptomics, proteomics and metabolomics in both sexes to capture the earliest pathological window rather than end-stage disease. It is the source of the metabolic arm of the LVNC8 mechanism and of the sex-dimorphism observation: female animals are more severely affected.

Species

Mouse

Genotype

Prdm16csp1/wt (systemic, monoallelic Prdm16 inactivation)

Genes

PRDM16 hgnc:14000

Publication

PMID:37842925

Pathograph links

Cardiac Metabolic Dysregulation recapitulates fidelity: moderate observes: molecular Metabolomic profiling of cardiac tissue defines the substrate-utilization and oxidative-stress changes this node asserts, at the earliest detectable stage.

Limitations: The metabolic phenotype is sex-dimorphic in this model and no equivalent human cardiac metabolomic data exist for PRDM16 carriers, so neither the magnitude nor the sex dependence has been confirmed in patients.

Readouts

Cardiac glutathione and inosine monophosphate

Targeted metabolomics of Prdm16csp1/wt cardiac tissue.

Direction: ALTERED

Interpretation: Falling glutathione with rising inosine monophosphate is read by the authors as oxidative stress plus dysregulated energetics, which is the content of this node.

Show evidence (1 reference)

PMID:37842925 SUPPORT Model Organism

"Prdm16csp1/wt cardiac tissue revealed diminished glutathione (GSH) and increased inosine monophosphate (IMP) levels indicating oxidative stress and a dysregulated energetics, respectively."

Reports both measurements and the directions this readout records.

Cardiac intermediary metabolite pools

Untargeted metabolomics across amino acid, glycerol, glycolytic and tricarboxylic acid cycle pathways in both sexes.

Direction: DECREASED

Interpretation: Broad reduction across central carbon and amino acid metabolism is the substrate-utilization deficit underlying this node.

Show evidence (1 reference)

PMID:37842925 SUPPORT Model Organism

"Prdm16csp1/wt cardiac tissue of both sexes showed reductions in metabolites associated with amino acid as well as glycerol metabolism, glycolysis, and the tricarboxylic acid cycle."

Reports the measured direction across the metabolite classes named in this readout.

Show evidence (1 reference)

PMID:37842925 SUPPORT Model Organism

"Metabolic alterations and transcriptional dysregulation in Prdm16csp1/wt affect cardiac tissue."

Attests that this model is informative for the cardiac metabolic node specifically, locating the metabolic alterations in cardiac tissue rather than in the adipose biology PRDM16 is better known for.

Left Ventricular Dilation and Systolic Dysfunction partially recapitulates fidelity: low observes: organism Systolic performance is reduced, matching the human phenotype, but the hearts are hypoplastic rather than dilated.

Limitations: Only the systolic-dysfunction half of this node is reproduced. Chamber geometry moves the wrong way: hypoplastic hearts are not dilated hearts, the same divergence the Q187X heterozygote shows. Both monoallelic mouse models therefore fail on the dilation component, which is worth weighing before treating either as a model of the remodeling process.

Readouts

Systolic performance

Echocardiographic systolic function in male and female Prdm16csp1/wt mice up to 8 months.

Direction: DECREASED

Interpretation: Diminished systolic performance is the component of this node the model does reproduce; the sex difference is a property of the model with no confirmed human counterpart.

Show evidence (1 reference)

PMID:37842925 SUPPORT Model Organism

"Prdm16csp1/wt mice are viable up to 8 months, develop hypoplastic hearts, and diminished systolic performance that is more pronounced in female mice."

Reports both the systolic deficit this readout measures and the hypoplastic chamber geometry that limits the link.

Show evidence (1 reference)

PMID:37842925 SUPPORT Model Organism

"Monoallelic, global Prdm16 mutation diminishes cardiac performance in Prdm16csp1/wt mice."

Attests that the monoallelic model does report on cardiac performance, which is the half of this node it partially recapitulates.

Show evidence (1 reference)

PMID:37842925 SUPPORT Model Organism

"This study performed in-depth pathophysiological and molecular analyses of male and female Prdm16csp1/wt mice that carry systemic, monoallelic Prdm16 gene inactivation."

Establishes the model's genotype as monoallelic and systemic, which is what makes it the closest available match to the human heterozygous state.

Prdm16 cardiomyocyte-specific deletion mouse (conduction-system phenotype)

An independently generated cardiomyocyte-specific Prdm16 deletion, analysed by combined single-cell RNA and ATAC sequencing. It is kept separate from the Prdm16cKO model above because it interrogates a different arm of the mechanism: rather than the compact-versus-trabecular axis, it establishes that PRDM16 suppresses conduction-system and atrial fates, and that its loss expands the distal ventricular conduction system. This is the only in vivo source for the conduction and arrhythmia arm of this entry.

Species

Mouse

Genotype

Prdm16lox/lox;Sm22alpha-Cre (called Prdm16cKO in the paper), deleting Prdm16 exon 9 in cardiomyocytes from early cardiac development onward

Genes

PRDM16 hgnc:14000

Publication

PMID:39304345

Pathograph links

Ventricular Conduction System Hyperplasia and Atrial-Fate Derepression recapitulates fidelity: high observes: tissue Developmental myocardial Prdm16 loss expands the distal ventricular conduction system, the structural change this node asserts.

Limitations: The Sm22alpha-Cre driver is not cardiomyocyte-exclusive: the authors report that it also eliminates PRDM16 in smooth muscle cells, and argue the cardiomyocyte loss is the primary culprit on the grounds that smooth muscle coverage was unaffected. Deletion is also developmental, where patients carry partial lifelong haploinsufficiency; whether that produces conduction-system expansion of comparable extent has not been shown, and no human histological counterpart is available.

Readouts

Distal ventricular conduction system extent

Histological and single-cell assessment of conduction-system tissue within the ventricular myocardium.

Direction: INCREASED

Interpretation: Hyperplasia of the distal conduction system is the direct measurement behind this node.

Show evidence (1 reference)

PMID:39304345 SUPPORT Model Organism

"Myocardial loss of PRDM16 during development resulted in hyperplasia of the (distal) ventricular conduction system."

Reports the measurement and its direction in this model.

Show evidence (1 reference)

PMID:39304345 SUPPORT Model Organism

"Hence, PRDM16 plays an indispensable role during cardiac development by driving ventricular working cardiomyocyte identity."

Attests the model's standing for this node: the conduction-system finding is the paper's basis for concluding that PRDM16 drives ventricular working cardiomyocyte identity against alternative fates.

Arrhythmia and Ventricular Pre-excitation partially recapitulates fidelity: moderate observes: organism The model develops abnormal postnatal electrophysiology and premature death, giving an in vivo arrhythmic phenotype downstream of the conduction-system expansion.

Limitations: The model reports abnormal electrophysiology and premature death, not ventricular pre-excitation specifically. The accessory-pathway phenotype that names this node is documented in a human PRDM16 carrier and has no demonstrated counterpart in this mouse, so the model supports the arrhythmia half of the node and not the pre-excitation half.

Readouts

Postnatal cardiac electrophysiology

Electrophysiological assessment of postnatal hearts after cardiomyocyte-specific Prdm16 deletion.

Direction: ALTERED

Interpretation: Abnormal postnatal electrophysiology culminating in premature death is the arrhythmic outcome this model reports.

Show evidence (2 references)

PMID:39304345 SUPPORT Model Organism

"cardiomyocyte-specific deletion of Prdm16 during cardiac development results in contractile dysfunction and abnormal electrophysiology of the postnatal heart, resulting in premature death"

Reports the electrophysiological abnormality and its lethal outcome in this model.

+ 1 more reference

Show evidence (1 reference)

PMID:39304345 SUPPORT Model Organism

"The observed prolonged QRS is indeed compatible with defects in the distal VCS"

The authors' own reading of their result, tying the measured conduction abnormality back to the distal conduction-system defect this model produces. That is precisely what makes the model informative for an arrhythmia node fed by conduction-system hyperplasia, rather than merely coincident with one.

Show evidence (2 references)

PMID:39304345 SUPPORT Model Organism

"By combined RNA+ATAC single-cell sequencing, we found that PRDM16 favors ventricular working cardiomyocyte identity, by opposing the activity of master regulators of ventricular conduction and atrial fate."

Establishes what this model was used to determine and the single-cell method that grounds the cell-fate claim.

PMID:39304345 SUPPORT Model Organism

"Although our Sm22α-Cre driver also eliminated PRDM16 expression in SMCs"

The authors' own statement of the driver's off-target, recorded here because the model's genotype would otherwise be read as restricted to cardiomyocytes. They go on to argue the cardiomyocyte loss is the primary culprit, but the smooth-muscle deletion is real and is why this link carries that caveat.

Zebrafish prdm16 haploinsufficiency and truncation model

The original functional model accompanying the discovery that PRDM16 mutation causes the cardiomyopathy of 1p36 deletion syndrome and a share of nonsyndromic LVNC and DCM. Both reduced prdm16 dose and a human truncation allele were modeled, producing contractile dysfunction, partial cardiomyocyte uncoupling, and impaired cardiomyocyte proliferative capacity. It is the earliest evidence tying the proliferative arm of this mechanism to the human genotype.

Species

Zebrafish

Genotype

prdm16 knockdown (haploinsufficiency) and human PRDM16 truncation mutant expression

Genes

PRDM16 hgnc:14000

Publication

PMID:23768516

Pathograph links

Impaired Cardiomyocyte Proliferation recapitulates fidelity: moderate observes: cellular Reduced prdm16 dose and a human truncation allele both impair cardiomyocyte proliferative capacity, the claim this node makes.

Limitations: Zebrafish cardiomyocytes retain proliferative and regenerative capacity that mammalian cardiomyocytes lose after birth, so the baseline biology of the readout differs from the human one. The zebrafish heart is also two-chambered and has no compact-versus-trabecular left ventricular architecture, so this model cannot address the chamber-specific arm of the mechanism at all.

Show evidence (1 reference)

PMID:23768516 SUPPORT Model Organism

"Modeling of PRDM16 haploinsufficiency and a human truncation mutant in zebrafish resulted in both contractile dysfunction and partial uncoupling of cardiomyocytes and also revealed evidence of impaired cardiomyocyte proliferative capacity."

Reports the proliferative deficit in both arms of the model.

Left Ventricular Dilation and Systolic Dysfunction partially recapitulates fidelity: low observes: organism Contractile dysfunction is reproduced; ventricular dilation is not assessable in this organism.

Limitations: The zebrafish heart has a single ventricle with no left-ventricular counterpart, so the chamber-specific dilation this node names cannot be observed here. Only the contractile-dysfunction component transfers, and the partial cardiomyocyte uncoupling reported alongside it has no established human correlate in LVNC8.

Show evidence (1 reference)

PMID:23768516 SUPPORT Model Organism

"Modeling of PRDM16 haploinsufficiency and a human truncation mutant in zebrafish resulted in both contractile dysfunction and partial uncoupling of cardiomyocytes and also revealed evidence of impaired cardiomyocyte proliferative capacity."

Reports the contractile dysfunction that is the transferable half of this link.

Show evidence (1 reference)

PMID:23768516 SUPPORT Model Organism

"Modeling of PRDM16 haploinsufficiency and a human truncation mutant in zebrafish resulted in both contractile dysfunction and partial uncoupling of cardiomyocytes and also revealed evidence of impaired cardiomyocyte proliferative capacity."

Establishes that both the dose-reduction and human-allele arms of the model were built and what cardiac phenotypes they produced.

Cardiac-specific Prdm16 conditional knockout mouse (conduction and fibrosis phenotype)

Cardiac-restricted Prdm16 null model phenotyped by electrocardiography, fibrosis histology and left ventricular RNA sequencing. It is the only model in this entry that measures TGF-beta pathway activity in vivo and then tests it pharmacologically: TGF-beta signaling is activated in Prdm16-null hearts, but blocking the TGF-beta receptor does not rescue the conduction defect. That negative rescue result separates the fibrotic and conduction arms of the mechanism, and the accompanying ion-channel transcript dysregulation offers a TGF-beta-independent route to the arrhythmia node.

Species

Mouse

Genotype

Cardiac-specific Prdm16 conditional knockout via alpha-MHC (Myh6)-Cre (Prdm16-null hearts); the driver is not named in this paper's own abstract-only record here and is attributed by PMID:37395136, which identifies its model as similar to Nam et al's Myh6-Cre knockout

Genes

PRDM16 hgnc:14000

Publication

PMID:32083975

Pathograph links

TGF-beta Signaling Dysregulation recapitulates fidelity: moderate observes: molecular TGF-beta signaling is activated in Prdm16-null hearts at both ligand transcript and downstream effector level, the direction predicted by PRDM16 acting as a repressor of TGFB transcription.

Limitations: This model's direction conflicts with the Prdm16Q187X heterozygote, which shows age-dependent loss of TGF-beta expression. The two differ in allele class (complete cardiac null versus a heterozygous nonsense variant), dose and timepoint. The Q187X paper proposes that PRDM16 regulates TGF-beta bidirectionally in a temporally-dependent manner, which would make the two findings phases of one mechanism; that has not been tested across models, so the sign of the TGF-beta change in human LVNC8 should not be inferred from either model alone. The driver is alpha-MHC (Myh6)-Cre, attributed by PMID:37395136 rather than stated in this paper's own record here, and it matters: Myh6-Cre knockouts are reported to give hypertrophy in one model and LV dilation in another, and a later paper judged the earlier conditional Prdm16 lines not to mirror the patient LVNC phenotype.

Readouts

Myocardial TGF-beta ligand transcripts and Smad2 phosphorylation

Quantitative real-time PCR for Tgfb1-3 and immunoblot for phosphorylated Smad2 in Prdm16-null hearts.

Direction: INCREASED

Interpretation: Raised ligand transcripts together with increased phospho-Smad2 is pathway activation measured at two levels rather than a transcript change alone.

Show evidence (1 reference)

PMID:32083975 SUPPORT Model Organism

"Moreover, TGF-β signaling was activated in Prdm16-null hearts, as evidenced by increased Tgfb1-3 transcript levels and phosphorylated Smad2."

Reports both measurements and the activation direction this readout records.

Show evidence (1 reference)

PMID:32083975 SUPPORT Model Organism

"Moreover, TGF-β signaling was activated in Prdm16-null hearts, as evidenced by increased Tgfb1-3 transcript levels and phosphorylated Smad2."

Attests that this model is informative for the TGF-beta node: it is the in vivo demonstration that removing PRDM16 de-represses TGF-beta signaling, which is what the promoter-binding work predicts.

Arrhythmia and Ventricular Pre-excitation partially recapitulates fidelity: moderate observes: organism Prdm16-null hearts show measurable conduction and repolarization abnormalities (prolonged QRS and QTc) alongside dysregulated ion channel transcripts, giving a TGF-beta-independent substrate for the arrhythmia node.

Limitations: The phenotype is conduction slowing and repolarization prolongation, not the accessory-pathway pre-excitation that names this node; no pre-excitation is reported in this model. Blocking the TGF-beta receptor does not reverse the conduction abnormality, so the arrhythmic substrate here is not downstream of the TGF-beta arm and should not be treated as such.

Readouts

QRS duration and QTc interval

Surface electrocardiography in cardiac-specific Prdm16 knockout mice versus wild-type.

Direction: INCREASED

Interpretation: Prolonged QRS and QTc are the quantitative conduction and repolarization abnormalities behind this node in this model.

Show evidence (1 reference)

PMID:32083975 SUPPORT Model Organism

"QRS duration and QTc interval increased significantly in cardiac-specific Prdm16 knockout animals compared with wild-type mice."

Reports both electrocardiographic measurements and their direction.

Ventricular ion channel transcript expression

RNA sequencing of left ventricular tissue, assessed for ion channel gene expression.

Direction: ALTERED

Interpretation: Dysregulation of Kcne1, Scn5a, Cacna1h and Cacna2d2 is the proposed molecular basis of the conduction phenotype and is independent of the TGF-beta arm.

Show evidence (1 reference)

PMID:32083975 SUPPORT Model Organism

"Prdm16-null hearts experienced dysregulated expression of ion channel genes, including Kcne1, Scn5a, Cacna1h, and Cacna2d2."

Names the dysregulated channel genes this readout measures.

Show evidence (1 reference)

PMID:32083975 SUPPORT Model Organism

"However, the inhibition of TGF-β receptor did not reverse the aberrations in conduction in cardiac-specific Prdm16 knockout mice."

A pharmacological rescue that failed, which is what makes this model informative for the arrhythmia node specifically: it establishes the conduction phenotype as separable from the TGF-beta arm rather than downstream of it.

Show evidence (1 reference)

PMID:32083975 SUPPORT Model Organism

"We used cardiac-specific Prdm16 conditional knockout mice to examine cardiac function by electrocardiography."

Establishes the model and the electrophysiological phenotyping that makes it usable for the conduction and arrhythmia arm of this entry.

Sex-stratified cardiac-specific Prdm16 conditional knockout mouse

A cardiac-specific Prdm16 knockout generated as the animal arm of a multi-institutional 1p36 deletion cohort study and analysed by sex, with echocardiography at 4 and 6 to 7 months and fibrosis histology at 7 months. Its value is that the sex effect it reports is paired with human data in the same paper, making it the one place in this entry where a model-derived observation is tested against patients rather than only asserted.

Species

Mouse

Genotype

Cardiac-specific Prdm16 conditional knockout via alpha-MHC (Myh6)-Cre, analysed by sex

Genes

PRDM16 hgnc:14000

Publication

PMID:37395136

Pathograph links

Left Ventricular Dilation and Systolic Dysfunction partially recapitulates fidelity: moderate observes: organism Contractile dysfunction and fibrosis develop with an incidence and severity that differ by sex, more severe in females, and female animals carry significantly elevated mortality.

Limitations: The reported outcome is contractile dysfunction with fibrosis rather than chamber dilation specifically, so this link covers the systolic-failure half of the node. The model is a cardiac-restricted null, whereas LVNC8 patients are germline heterozygotes, and the human comparison in the same paper is a contiguous-gene-deletion cohort rather than nonsyndromic PRDM16 variant carriers.

Readouts

Sex-stratified contractile dysfunction and fibrosis

Echocardiography at 4 and 6 to 7 months with fibrosis histology and qPCR at 7 months, analysed separately in male and female animals.

Direction: DECREASED

Interpretation: Reduced contractile function with greater fibrosis in females is the measured phenotype; the sex difference is the finding, not an incidental stratification.

Show evidence (1 reference)

PMID:37395136 SUPPORT Model Organism

"We find sex-specific differences in the incidence and the severity of contractile dysfunction and fibrosis in female Prdm16 conditional knockout mice."

Reports the sex-stratified contractile and fibrotic measurements this readout records.

Show evidence (2 references)

PMID:37395136 SUPPORT INDIRECT Model Organism

"female Prdm16 conditional knockout mice demonstrate significantly elevated risk of mortality (P=0.0003)"

Recorded on the link rather than as a readout because mortality is a downstream consequence, not a measure of chamber dilation or systolic function. It is kept because it sizes the severity of the sex effect this link records. Directness is INDIRECT: survival is attributed to the contractile phenotype by co-occurrence in the same animals rather than by a demonstrated mechanism.

+ 1 more reference

Show evidence (1 reference)

PMID:37395136 SUPPORT Model Organism

"A cardiac-specific Prdm16 knockout mouse (Prdm16 conditional knockout) was generated."

Establishes that the study built its own animal model alongside the patient cohort.

{ }

Source YAML

click to show

name: Left Ventricular Noncompaction 8
creation_date: "2026-08-17T21:00:00Z"
category: Genetic
description: >-
  Left ventricular noncompaction 8 (LVNC8) is the PRDM16-associated form of
  inherited left ventricular noncompaction and dilated cardiomyopathy. PRDM16
  encodes a zinc-finger transcription factor that is enriched in the compact
  myocardium of the developing left ventricle, where it activates
  compact-myocardial genes, represses trabecular-myocardial genes, restrains
  TGF-beta signaling to permit cardiomyocyte proliferation, opposes master
  regulators of ventricular conduction and atrial fate, and supports cardiac
  metabolic homeostasis. Haploinsufficient or truncating PRDM16 variants were
  first identified within the 1p36 deletion syndrome critical region and were
  subsequently shown to cause nonsyndromic LVNC and dilated cardiomyopathy
  (DCM), producing a ventricular phenotype that spans isolated noncompaction,
  noncompaction with dilation, and pure dilation without excess trabeculation.
  MONDO frames the entity through the PRDM16-dilated-cardiomyopathy axis ("any
  familial isolated dilated cardiomyopathy in which the cause of the disease is
  a mutation in the PRDM16 gene") while the disease label foregrounds
  noncompaction; both framings are correct descriptions of the same genotype
  and are reconciled below.
synonyms:
- LVNC8
- left ventricular noncompaction type 8
- PRDM16 familial isolated dilated cardiomyopathy
- familial isolated dilated cardiomyopathy caused by mutation in PRDM16
- CMD1LL
disease_term:
  preferred_term: left ventricular noncompaction 8
  term:
    id: MONDO:0014152
    label: left ventricular noncompaction 8
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0014152
      label: left ventricular noncompaction 8
    mapping_predicate: skos:exactMatch
parents:
- Left Ventricular Noncompaction
- Dilated Cardiomyopathy
- Genetic Disorder
notes: >-
  Related entries: kb/disorders/Left_Ventricular_Noncompaction.yaml
  (MONDO:0018901, the polygenic umbrella LVNC entry) and
  kb/disorders/Dilated_Cardiomyopathy.yaml /
  Dilated_Cardiomyopathy_1AA.yaml (ACTN2, which models an analogous
  noncompaction-or-dilation dual phenotype). PRDM16 is also the gene
  underlying the cardiomyopathy component of 1p36 deletion syndrome
  (PMID:23768516); that syndromic, contiguous-gene-deletion context is
  distinct from this nonsyndromic, single-gene entity and its mechanism is
  not modeled here. Data from 1p36 deletion cohorts are used where they
  isolate PRDM16's own contribution by comparing deletions that remove the
  gene against deletions that spare it (PMID:37395136, supporting the
  penetrance record in `prevalence` and the transplant-endpoint evidence);
  every such record states that its population is the deletion syndrome
  rather than nonsyndromic LVNC8, because other genes in the deletion
  interval may modify the risk.
  PRDM16 is independently well known as the master regulator of brown/beige
  adipocyte fate; that adipose biology is unrelated to the cardiac mechanism
  curated below and was excluded during literature triage (NEC risk noted on
  issue 8747).

  Sources fetched but deliberately not cited: DOI:10.1007/s12265-023-10459-6
  (Walsh 2023) and DOI:10.1016/j.jacc.2014.08.030 (Arbustini 2014) resolved to
  empty ("content_type: unavailable") DOI-keyed caches, so both were re-fetched
  and cited under their PMID identifiers instead (PMID:38019448, PMID:25443708)
  once full text was confirmed available. At the time PMID citations were
  snippet-validated by tooling and DOI citations were not, because `DOI:` was
  then in `skip_prefixes`; PR 11931 removed it, so both are now checked. DOI:10.1038/ncb3411 (Kodo 2016) and
  DOI:10.1161/CIRCULATIONAHA.121.056666 (Wu 2022) are the same papers already
  cited here under PMID:27642787 and PMID:34915728 respectively,  so no
  separate DOI-keyed citation was added. DOI:10.17169/refubium-41680 (Theisen
  2024, an unpublished doctoral thesis) reports the same Prdm16csp1/wt mouse
  line and sex-specific metabolic phenotype as the peer-reviewed
  PMID:37842925 (Kuhnisch et al. 2023), which is cited instead. The ESC 2023
  cardiomyopathy-guidelines commentary (DOI:10.1093/eurheartjsupp/suae002) is
  a generic classification-scheme overview with no LVNC8- or PRDM16-specific
  quotable claim beyond what PMID:25443708 already supports with concrete
  criteria, so it was left uncited rather than cited for its abstract alone.

  A second falcon deep-research round (2026-09-06) added PMID:32083975
  (cardiac-specific Prdm16 null: TGF-beta activation, QRS/QTc prolongation,
  ion-channel dysregulation), PMID:37395136 (1p36 deletion cohort with a
  sex-stratified Prdm16 knockout), PMID:31959004 and PMID:39420976 (LVNC
  outcome and prevalence meta-analyses), and trials NCT06024759 and
  NCT03572569. Sources from that round deliberately not cited:
  DOI:10.20944/preprints202507.1652.v1 (Martinez-Tittonel 2025) is an
  unpublished Preprints.org preprint whose diagnostic-criteria content
  duplicates what PMID:25443708 already supports from a peer-reviewed source;
  NCT04265040 (TORCH-Plus) is a broad multi-cardiomyopathy cohort with no
  LVNC- or PRDM16-specific arm; and DOI:10.1101/2020.01.03.19015602 is the
  medRxiv preprint of PMID:33500567, cited here under its PMID. The remaining
  DOIs that round returned resolve to papers already cited under their PMIDs.
discussions:
- discussion_id: gap_lvnc8_noncompaction_vs_dcm_nosology
  prompt: >-
    Is PRDM16-associated cardiomyopathy best classified as a form of left
    ventricular noncompaction, a form of dilated cardiomyopathy, or a single
    genotype that produces a phenotypic spectrum spanning both labels?
  kind: INTERPRETATION
  status: OPEN
  attaches_to:
  - pathophysiology#Failed Ventricular Compaction
  - pathophysiology#Left Ventricular Dilation and Systolic Dysfunction
  rationale: >-
    MONDO:0014152 is defined through the DCM axis ("any familial isolated
    dilated cardiomyopathy...caused by...PRDM16") even though its label and
    OMIM entry (615373) foreground noncompaction. The primary literature
    resolves this as a genuine spectrum rather than a labeling error: the
    founding report found PRDM16 mutations in both nonsyndromic LVNC and DCM
    cohorts, a large systematic rare-variant study found PRDM16 (with MYH7 and
    ACTN2) uniquely enriched in LVNC specifically among cardiomyopathy genes,
    a contemporary review reports that missense variants track with DCM while
    nonsense/frameshift variants track with LVNC, and mouse/human mechanistic
    work shows PRDM16 loss produces both noncompaction (failure of
    compact-myocardium specification) and LV dilation (impaired cardiomyocyte
    proliferation and TGF-beta-driven remodeling) from the same lesion. This
    dismech entry curates LVNC8 as its own genotype-defined node distinct from
    the polygenic LVNC umbrella entry, modeling both the noncompaction and the
    dilation/heart-failure branches as parallel downstream consequences of the
    same PRDM16 lesion rather than picking one label over the other.
  evidence:
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In conclusion, mutation of PRDM16 causes the cardiomyopathy in 1p36
      deletion syndrome as well as a proportion of nonsyndromic LVNC and DCM.
    explanation: >-
      The founding genetic report establishes PRDM16 as causal for both LVNC
      and DCM cohorts, directly supporting a shared-genotype spectrum rather
      than two separate diseases.
  - reference: PMID:33500567
    reference_title: Systematic large-scale assessment of the genetic architecture of left ventricular noncompaction reveals diverse etiologies.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In contrast, truncating variants in MYH7, ACTN2, and PRDM16 were uniquely
      associated with LVNC and may reflect a distinct LVNC etiology.
    explanation: >-
      A large systematic rare-variant study specifically flags PRDM16 as one
      of few genes with LVNC-specific (rather than shared DCM/HCM) enrichment,
      supporting genuine noncompaction biology alongside the DCM framing.
  - reference: PMID:39337275
    reference_title: "Unveiling the Spectrum of Minor Genes in Cardiomyopathies: A Narrative Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Missense variants in PRDM16 were primarily associated with DCM, whereas
      nonsense and frameshift mutations were associated with LVNC
    explanation: >-
      A contemporary narrative review reports a variant-class-specific
      genotype-phenotype correlation (missense to DCM, nonsense/frameshift to
      LVNC) that directly explains why the same gene produces both labeled
      phenotypes rather than one being a misclassification of the other.
- discussion_id: gap_lvnc8_tgfbeta_direction_conflict
  prompt: >-
    Does loss of PRDM16 raise or lower TGF-beta signaling in the myocardium,
    and which direction operates in human LVNC8?
  kind: HUMAN_MODEL_MISMATCH
  status: OPEN
  attaches_to:
  - pathophysiology#TGF-beta Signaling Dysregulation
  - pathophysiology#Impaired Cardiomyocyte Proliferation
  rationale: >-
    The mechanistic premise is that PRDM16 represses TGFB transcription, so
    losing it should de-repress the pathway. A cardiac-specific Prdm16 null
    mouse shows exactly that: raised Tgfb1-3 transcripts and increased
    phospho-Smad2. The heterozygous Prdm16Q187X knock-in, which is the
    genotype-matched model for a human LVNC8 patient, instead shows an
    age-dependent loss of TGF-beta expression. Human patient-derived
    iPSC-cardiomyocytes sit on the activation side, since their proliferative
    deficit is attributed to abnormal activation of TGF-beta signalling. The
    models differ in allele class (complete cardiac null versus heterozygous
    nonsense), dose, Cre driver, and the age at which TGF-beta was measured,
    and no study has compared them directly. Cre driver is worth naming among
    these: the authors of the ventricular-identity study state that using
    different Cre driver strains made the phenotypic outcome of Prdm16 animal
    studies highly heterogeneous, and the 1p36 cohort paper reports that
    Myh6-Cre knockouts alone gave hypertrophy in one model and LV dilation in
    another. A reconciliation has in fact been proposed: the Q187X paper
    concludes that PRDM16 regulates TGF-beta bidirectionally in a
    temporally-dependent manner, which would make activation and
    age-dependent loss two phases of one mechanism rather than a
    contradiction. That proposal is this entry's leading candidate but has
    not been tested against the other models, so the sign at any given
    developmental stage in patients remains open. This matters beyond bookkeeping because
    TGF-beta inhibition reversed the proliferative phenotype in the iPSC
    system and so is the one mechanistically motivated therapeutic direction
    in this entry; a mistaken sign would point that intervention the wrong
    way. Note also that TGF-beta receptor inhibition did not reverse the
    conduction abnormality in the null mouse, so even where the pathway is
    activated it does not account for the whole phenotype.
  evidence:
  - reference: PMID:32083975
    reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Moreover, TGF-β signaling was activated in Prdm16-null hearts, as
      evidenced by increased Tgfb1-3 transcript levels and phosphorylated
      Smad2.
    explanation: >-
      The activation arm of the conflict, measured at ligand transcript and
      downstream effector level in a cardiac-specific null.
  - reference: PMID:38113297
    reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller
      ventricular dimensions, heightened fibrosis, and age-dependent loss
      of TGF-β expression.
    explanation: >-
      The opposing arm of the conflict this discussion records: the
      genotype-matched heterozygote loses rather than gains TGF-beta
      expression with age. Graded SUPPORT because the discussion's claim is
      that the direction is unsettled, which this finding establishes rather
      than contradicts.
  - reference: PMID:27642787
    reference_title: "iPSC-derived cardiomyocytes reveal abnormal TGF-β signalling in left ventricular non-compaction cardiomyopathy."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      LVNC iPSC-CMs have decreased proliferative capacity due to abnormal
      activation of TGF-β signalling.
    explanation: >-
      Human-derived cells fall on the activation side and are the reason the
      question is not purely a mouse-model curiosity.
  - reference: PMID:38113297
    reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      PRDM16 bidirectionally regulates TGFβ signaling in a
      temporally-dependent manner
    explanation: >-
      The candidate reconciliation, offered by the same paper that reports the
      age-dependent loss: if regulation is bidirectional and time-dependent,
      activation and later loss are phases of one mechanism rather than
      opposing findings. Recorded as the leading hypothesis, not as a
      settled answer, since it has not been tested against the other models.
  - reference: PMID:37395136
    reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Possible explanations for these variations include efficiency of the
      Cre driver, the cell type(s) in which Prdm16 is deleted, the timing of
      deletion, and background genetic effects.
    explanation: >-
      Names the technical variables that plausibly generate divergence
      between Prdm16 knockout studies, which is why this discussion lists Cre
      driver and timing alongside allele class. Directness is INDIRECT: the
      authors offer these for phenotypic variation across Prdm16 models
      generally, not for the TGF-beta direction conflict specifically.
- discussion_id: gap_lvnc8_female_predominance
  prompt: >-
    Why is PRDM16-associated cardiomyopathy more severe in females, and does
    the sex effect seen in 1p36 deletion carriers extend to nonsyndromic LVNC8?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Left Ventricular Dilation and Systolic Dysfunction
  - pathophysiology#Cardiac Metabolic Dysregulation
  rationale: >-
    A female-predominant severity signal appears independently in two mouse
    lines and in patients. Monoallelic Prdm16csp1/wt mice show diminished
    systolic performance that is more pronounced in females, alongside
    sex-divergent cardiac metabolism: triacylglycerides accumulate only in
    male hearts, and metabolic modelling assigns reduced fatty acid
    utilisation to males and lower glucose utilisation to females. A
    separately generated cardiac-specific Prdm16 knockout shows sex
    differences in the incidence and severity of contractile dysfunction and
    fibrosis, with significantly elevated mortality in females. In the human
    1p36 deletion cohort the same direction appears, 34.5% of PRDM16-deleted
    females developing cardiomyopathy versus 16.7% of males, though that
    comparison did not reach significance at the available sample size. What
    is missing is a mechanism connecting the sex-divergent substrate
    utilisation to the sex-divergent contractile outcome, and any test of the
    effect in nonsyndromic PRDM16 variant carriers, where every published
    cohort is too small to stratify by sex. Until then, sex should not be used
    to stratify surveillance in LVNC8.
  evidence:
  - reference: PMID:37395136
    reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Among those PRDM16 deleted, 34.5% of females developed cardiomyopathy
      versus 16.7% of their male counterparts (P=0.2).
    explanation: >-
      The human sex comparison. Directness is INDIRECT because the cohort is
      1p36 deletion syndrome rather than nonsyndromic LVNC8, and the
      difference does not reach significance, so it establishes the question
      rather than the answer.
  - reference: PMID:37842925
    reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      An accumulation of triacylglycerides exclusively in male Prdm16csp1/wt
      hearts suggests a sex-specific metabolic adaptation.
    explanation: >-
      Identifies a sex-divergent metabolic difference in the monoallelic
      model, the candidate substrate for the sex effect and the reason this
      gap attaches to the metabolic node as well as the contractile one.
  - reference: PMID:37395136
    reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      female Prdm16 conditional knockout mice demonstrate significantly
      elevated risk of mortality (P=0.0003)
    explanation: >-
      Independent mouse replication of the female-predominant severity signal,
      in a different line from the metabolic study.
pathophysiology:
- name: PRDM16 Loss-of-Function Variant
  biological_scale: MOLECULAR
  description: >-
    Heterozygous truncating (nonsense, frameshift) or missense PRDM16 variants
    reduce the dose or activity of the PRDM16 zinc-finger transcription
    factor. Variants cluster across the gene's 17 exons and were first mapped
    within the terminal 1p36 deletion syndrome critical region before being
    confirmed as an independent cause of nonsyndromic disease. A contemporary
    review reports a variant-class correlation: missense variants track with
    DCM, while nonsense and frameshift (loss-of-function) variants track with
    LVNC, and PRDM16 is predicted to be highly intolerant of loss-of-function
    variation.
  genetic_context:
    functional_impact_category: LOSS_OF_FUNCTION
    allele_type: SNV_INDEL
    variant_origin: GERMLINE
    zygosity: HETEROZYGOUS
  locations:
  - preferred_term: heart left ventricle
    term:
      id: UBERON:0002084
      label: heart left ventricle
  evidence:
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Resequencing of PRDM16 in a cohort of 75 nonsyndromic individuals with
      LVNC detected three mutations, including one truncation mutant, one
      frameshift null mutation, and a single missense mutant.
    explanation: >-
      Directly documents the spectrum of PRDM16 loss-of-function and missense
      variants identified in nonsyndromic LVNC probands.
  - reference: PMID:38113297
    reference_title: Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report 2 probands with loss-of-function PRDM16 variants and
      pediatric left ventricular noncompaction cardiomyopathy.
    explanation: >-
      Confirms loss-of-function PRDM16 variants as the proximate genetic
      lesion in two independently ascertained pediatric probands.
  - reference: PMID:39337275
    reference_title: "Unveiling the Spectrum of Minor Genes in Cardiomyopathies: A Narrative Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Missense variants in PRDM16 were primarily associated with DCM, whereas
      nonsense and frameshift mutations were associated with LVNC
    explanation: >-
      Establishes the variant-class-specific genotype-phenotype correlation
      that motivates classifying this node's loss-of-function variants as the
      LVNC-associated lesion class.
  - reference: PMID:39337275
    reference_title: "Unveiling the Spectrum of Minor Genes in Cardiomyopathies: A Narrative Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PRDM16 is predicted to be highly intolerant to LOF
    explanation: >-
      Population-genetic constraint evidence supporting a dosage-sensitive,
      loss-of-function-intolerant gene consistent with dominant
      haploinsufficiency as the disease mechanism.
  downstream:
  - target: Loss of Compact Myocardium Transcriptional Identity
    description: >-
      Reduced PRDM16 dose removes its transcriptional activation of
      compact-myocardial genes and repression of trabecular-myocardial genes
      in left ventricular cardiomyocytes.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34915728
      reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Consequently, Prdm16cKO LV compact myocardial cardiomyocytes shifted
        from their normal transcriptomic identity to a transcriptional
        signature resembling trabecular myocardial cardiomyocytes or
        neurons.
      explanation: >-
        The connective "Consequently" makes this a causal statement about
        the edge itself, not about either node alone: cardiomyocyte-specific
        Prdm16 ablation is what shifts compact-myocardial cardiomyocytes out
        of their normal transcriptional identity.
  - target: Cardiac Metabolic Dysregulation
    description: >-
      Independent of the compact-myocardium transcriptional program,
      monoallelic Prdm16 loss produces early, sex-modified metabolic and
      oxidative-stress changes in cardiac tissue.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37842925
      reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        This study suggests that metabolic dysregulation is an early event
        in the PRDM16 associated cardiac pathology.
      explanation: >-
        Places metabolic dysregulation causally downstream of PRDM16 loss
        and early in the pathological sequence, which is the claim this edge
        makes.

- name: Loss of Compact Myocardium Transcriptional Identity
  biological_scale: CELLULAR
  role: effector
  description: >-
    PRDM16 is a compact-myocardium-enriched transcription factor that
    activates a compact-myocardial gene program while repressing a
    trabecular-myocardial gene program, in part through cooperation with the
    LV-enriched transcription factors TBX5 and HAND1. In cardiomyocyte-specific
    Prdm16 knockout mice, compact myocardial cardiomyocytes shift from a
    compact transcriptional identity toward one resembling trabecular
    myocardium or neurons, with reduced cardiomyocyte proliferation localized
    to the left ventricular compact layer and interventricular septum.
    Independently, single-cell RNA+ATAC sequencing shows PRDM16 favors
    ventricular working cardiomyocyte identity specifically by opposing the
    master regulators of ventricular conduction and atrial fate, so its loss
    also derepresses a conduction-system/atrial transcriptional program.
  cell_types:
  - preferred_term: cardiac muscle cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  locations:
  - preferred_term: heart left ventricle
    term:
      id: UBERON:0002084
      label: heart left ventricle
  evidence:
  - reference: PMID:34915728
    reference_title: PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      PRDM16 functioned mechanistically as a compact myocardium-enriched
      transcription factor that activated compact myocardial genes while
      repressing trabecular myocardial genes in LV compact myocardium.
    explanation: >-
      Mouse cardiomyocyte-specific knockout study directly establishes the
      dual activator/repressor transcriptional role of PRDM16 in specifying
      compact versus trabecular cardiomyocyte identity.
  - reference: PMID:34915728
    reference_title: PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Prdm16cKO LV compact myocardial cardiomyocytes shifted from their normal
      transcriptomic identity to a transcriptional signature resembling
      trabecular myocardial cardiomyocytes or neurons.
    explanation: >-
      Documents the specific transcriptional-identity-switch consequence of
      PRDM16 loss in LV compact myocardium.
  - reference: PMID:39304345
    reference_title: PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      PRDM16 favors ventricular working cardiomyocyte identity, by opposing
      the activity of master regulators of ventricular conduction and atrial
      fate.
    explanation: >-
      Independent single-cell RNA+ATAC-sequencing study in a mouse
      cardiomyocyte-specific Prdm16 deletion establishes that PRDM16 actively
      suppresses conduction-system and atrial cell-fate programs as part of
      maintaining ventricular working cardiomyocyte identity.
  downstream:
  - target: TGF-beta Signaling Dysregulation
    description: >-
      Loss of PRDM16-mediated repression of TGF-beta pathway genes,
      including direct repression of the TGFB3 promoter, de-represses
      TGF-beta receptor signaling in cardiomyocytes.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Mechanistic studies were undertaken in H9c2 cardiomyoblasts to show
        that PRDM16 binds TGFB3 promoter and represses its transcription.
      explanation: >-
        Direct promoter-binding and repression assay establishing that
        PRDM16 represses TGFB3, so loss of PRDM16 de-represses TGF-beta
        signaling. Evidence source is IN_VITRO because the mechanism was
        established in cultured H9c2 cardiomyoblasts.
  - target: Failed Ventricular Compaction
    description: >-
      Loss of the compact-myocardial gene program directly impairs the
      structural maturation of the compact ventricular wall.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34915728
      reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        These results demonstrate that disruption of proper specification of
        compact cardiomyocytes may play a key role in the pathogenesis of
        LVNC.
      explanation: >-
        States the causal step from loss of compact-cardiomyocyte
        specification to noncompaction pathogenesis, which is exactly this
        edge rather than either node in isolation.
  - target: Ventricular Conduction System Hyperplasia and Atrial-Fate Derepression
    description: >-
      Loss of PRDM16-mediated suppression of conduction-system and
      atrial-fate master regulators allows ectopic conduction-system tissue
      to expand within the ventricular myocardium.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:39304345
      reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Myocardial loss of PRDM16 during development resulted in hyperplasia
        of the (distal) ventricular conduction system.
      explanation: >-
        Reports the conduction-system expansion as a result of myocardial
        PRDM16 loss, supporting the edge from loss of ventricular
        working-cardiomyocyte identity to conduction-system hyperplasia.

- name: TGF-beta Signaling Dysregulation
  biological_scale: MOLECULAR
  role: effector
  description: >-
    PRDM16 normally binds the TGFB3 promoter and represses its transcription.
    Loss of PRDM16 releases this repression, producing increased TGF-beta
    receptor signaling in cardiomyocytes. Because TGF-beta signaling has an
    antiproliferative effect on cardiomyocytes, its dysregulated increase
    reduces cardiomyocyte proliferative capacity during the developmental
    window when compaction normally occurs. The INCREASED modifier records
    the majority position, supported by the promoter-repression mechanism,
    by patient-derived iPSC-cardiomyocytes, and by TGF-beta activation in
    Prdm16-null hearts. It is not unanimous: the genotype-matched
    heterozygous Prdm16Q187X mouse instead loses TGF-beta expression with
    age, and that model is linked below as FAILS_TO_RECAPITULATE this node.
    The unresolved sign is tracked in discussion
    gap_lvnc8_tgfbeta_direction_conflict and matters because TGF-beta
    inhibition is the one mechanistically motivated therapeutic direction
    this entry identifies.
  biological_processes:
  - preferred_term: transforming growth factor beta receptor signaling pathway
    modifier: INCREASED
    term:
      id: GO:0007179
      label: transforming growth factor beta receptor signaling pathway
  evidence:
  - reference: PMID:38113297
    reference_title: Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Mechanistic studies were undertaken in H9c2 cardiomyoblasts to show that
      PRDM16 binds TGFB3 promoter and represses its transcription.
    explanation: >-
      Direct biochemical evidence that PRDM16 represses TGFB3 transcription,
      establishing the molecular basis for TGF-beta pathway de-repression
      upon PRDM16 loss. H9c2 is a rat cardiomyoblast cell line, so this is
      cultured-cell (IN_VITRO) evidence, not a whole-animal model.
  - reference: PMID:27642787
    reference_title: iPSC-derived cardiomyocytes reveal abnormal TGF-β signalling in left ventricular non-compaction cardiomyopathy.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      TBX20 regulates the expression of TGF-β signalling modifiers including
      one known to be a genetic cause of LVNC, PRDM16, and genome editing of
      PRDM16 caused proliferation defects in iPSC-CMs.
    explanation: >-
      Independent iPSC-cardiomyocyte genome-editing evidence that PRDM16 loss
      causes the same TGF-beta-linked proliferation defect seen in the PRDM16
      patient-mutation studies.
  downstream:
  - target: Impaired Cardiomyocyte Proliferation
    description: >-
      Increased TGF-beta receptor signaling suppresses the proliferative
      expansion of developing left ventricular cardiomyocytes.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:27642787
      reference_title: "iPSC-derived cardiomyocytes reveal abnormal TGF-β signalling in left ventricular non-compaction cardiomyopathy."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        LVNC iPSC-CMs have decreased proliferative capacity due to abnormal
        activation of TGF-β signalling.
      explanation: >-
        Attributes the proliferative deficit directly to abnormal TGF-beta
        activation ("due to"), which is the causal claim of this edge.
        Evidence source is IN_VITRO because the finding is in
        patient-derived iPSC-cardiomyocytes.

- name: Cardiac Metabolic Dysregulation
  biological_scale: MOLECULAR
  role: effector
  description: >-
    Independently of the compact-myocardium transcriptional program,
    monoallelic Prdm16 loss produces early metabolic dysregulation in cardiac
    tissue: reduced amino-acid, glycerol, glycolytic, and
    tricarboxylic-acid-cycle metabolites, diminished glutathione with
    increased inosine monophosphate (indicating oxidative stress and
    dysregulated energetics),
    and up-regulation of two novel candidate cardiac metabolic regulators,
    PYROXD2 and PBXIP1. The phenotype is sex-modified: cardiac dysfunction
    and reduced glucose utilization are more pronounced in female mice, while
    triacylglyceride accumulation and reduced fatty-acid utilization are
    male-specific.
  biological_processes:
  - preferred_term: cellular response to oxidative stress
    modifier: INCREASED
    term:
      id: GO:0034599
      label: cellular response to oxidative stress
  evidence:
  - reference: PMID:37842925
    reference_title: Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Prdm16csp1/wt mice are viable up to 8 months, develop hypoplastic
      hearts, and diminished systolic performance that is more pronounced in
      female mice.
    explanation: >-
      Establishes the sex-modified severity of the metabolic/functional
      cardiac phenotype in a monoallelic Prdm16 mouse model.
  - reference: PMID:37842925
    reference_title: Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Prdm16csp1/wt cardiac tissue revealed diminished glutathione (GSH) and
      increased inosine monophosphate (IMP) levels indicating oxidative
      stress and a dysregulated energetics, respectively.
    explanation: >-
      Direct metabolomic evidence for oxidative stress and dysregulated
      cardiac energetics as an early consequence of PRDM16 loss.
  - reference: PMID:37842925
    reference_title: Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      On the level of transcripts and protein expression, Prdm16csp1/wt
      hearts demonstrate an up-regulation of pyridine nucleotide-disulphide
      oxidoreductase domain 2 (Pyroxd2) and the transcriptional regulator
      pre-B-cell leukaemia transcription factor interacting protein 1
      (Pbxip1).
    explanation: >-
      Identifies PYROXD2 and PBXIP1 as novel transcriptionally up-regulated
      candidate cardiac metabolic regulators downstream of PRDM16 loss.
  downstream:
  - target: Left Ventricular Dilation and Systolic Dysfunction
    description: >-
      Oxidative stress and dysregulated cardiac energetics contribute to
      diminished systolic performance independently of the
      compaction/TGF-beta axis.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37842925
      reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Prdm16csp1/wt mice are viable up to 8 months, develop hypoplastic
        hearts, and diminished systolic performance that is more pronounced
        in female mice.
      explanation: >-
        The same monoallelic Prdm16 model in which the metabolic and
        oxidative-stress changes are documented also shows diminished
        systolic performance. Directness is INDIRECT: the study establishes
        that both occur and positions metabolic dysregulation as the earlier
        event, but does not experimentally demonstrate that the metabolic
        change causes the contractile deficit.

- name: Impaired Cardiomyocyte Proliferation
  biological_scale: CELLULAR
  role: effector
  description: >-
    Cardiomyocytes carrying loss-of-function PRDM16 variants show reduced
    proliferative capacity and increased apoptosis. In induced pluripotent
    stem cell-derived cardiomyocytes (iPSC-CMs) generated from a PRDM16-Q187X
    proband, proliferation was significantly reduced and apoptosis increased,
    with transcriptional dysregulation of cardiac maturation genes including
    TGF-beta-associated transcripts; homozygous Prdm16-Q187X knock-in mice were
    embryonic lethal with an underdeveloped compact myocardium.
  cell_types:
  - preferred_term: cardiac muscle cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  evidence:
  - reference: PMID:38113297
    reference_title: Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Induced pluripotent stem cell-derived cardiomyocytes prepared from the
      PRDM16-Q187X proband demonstrated a statistically significant impairment
      in myocyte proliferation and increased apoptosis associated with
      transcriptional dysregulation of genes implicated in cardiac maturation,
      including TGF-β-associated transcripts.
    explanation: >-
      Patient-derived iPSC-cardiomyocyte data directly demonstrate the
      proliferation and apoptosis defect caused by a human loss-of-function
      PRDM16 variant.
  - reference: PMID:38113297
    reference_title: Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Homozygous Prdm16Q187X/Q187X mice demonstrated an underdeveloped compact
      myocardium and were embryonically lethal. Heterozygous
      Prdm16Q187X/WT mice demonstrated significantly smaller ventricular
      dimensions, heightened fibrosis, and age-dependent loss of TGF-β
      expression.
    explanation: >-
      Knock-in mouse model carrying the human PRDM16-Q187X variant confirms
      dose-dependent impairment of compact myocardial development.
  downstream:
  - target: Failed Ventricular Compaction
    description: >-
      Reduced cardiomyocyte proliferation in the developing compact
      myocardium limits the thickening and maturation of the compact
      ventricular wall.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Homozygous Prdm16Q187X/Q187X mice demonstrated an underdeveloped
        compact myocardium and were embryonically lethal.
      explanation: >-
        The same Q187X allele that impairs cardiomyocyte proliferation in
        patient-derived iPSC-cardiomyocytes produces an underdeveloped
        compact myocardium in vivo. Directness is INDIRECT: the
        proliferative deficit is the inferred proximate cause of the
        compaction failure rather than a measured intermediate in this
        experiment.
  - target: Left Ventricular Dilation and Systolic Dysfunction
    description: >-
      Reduced cardiomyocyte number and thinner compact/interventricular
      septal myocardium predispose to progressive ventricular dilation and
      contractile dysfunction.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23768516
      reference_title: "Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Modeling of PRDM16 haploinsufficiency and a human truncation mutant
        in zebrafish resulted in both contractile dysfunction and partial
        uncoupling of cardiomyocytes and also revealed evidence of impaired
        cardiomyocyte proliferative capacity.
      explanation: >-
        A single model shows impaired cardiomyocyte proliferative capacity
        alongside contractile dysfunction. Directness is INDIRECT: the two
        findings are reported together in one model and the ordering between
        them is an inference, not a demonstrated sequence.

- name: Failed Ventricular Compaction
  biological_scale: TISSUE
  role: effector
  description: >-
    Loss of PRDM16-driven compact myocardial specification and reduced
    compact-layer cardiomyocyte proliferation leave a thick, spongy
    trabeculated layer with deep intertrabecular recesses overlying a thinned
    compacted wall, predominantly affecting the left ventricle. In
    cardiomyocyte-specific Prdm16 knockout mice this produces biventricular
    noncompaction with LV-specific thinning of the compact myocardium and
    interventricular septum detectable from embryonic day 15.5.
  locations:
  - preferred_term: heart left ventricle
    term:
      id: UBERON:0002084
      label: heart left ventricle
  biological_processes:
  - preferred_term: cardiac ventricle morphogenesis
    term:
      id: GO:0003208
      label: cardiac ventricle morphogenesis
  evidence:
  - reference: PMID:34915728
    reference_title: PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific
      dilation and dysfunction, as well as biventricular noncompaction, which
      fully recapitulated LVNC in patients.
    explanation: >-
      Mouse model directly recapitulates the human noncompaction phenotype
      following cardiomyocyte-specific PRDM16 loss.
  - reference: PMID:31965688
    reference_title: "Cardiomyopathy due to PRDM16 mutation: First description of a fetal presentation, with possible modifier genes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Endocardial fibroelastosis was associated with non-compaction of the
      myocardium of the left ventricle.
    explanation: >-
      Human fetal pathology report documents left ventricular non-compaction
      as the structural cardiac lesion in a de novo PRDM16 nonsense variant.
  downstream:
  - target: Left Ventricular Dilation and Systolic Dysfunction
    description: >-
      The structurally abnormal, thinned compact wall is predisposed to
      progressive dilation and reduced contractile function.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34915728
      reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific
        dilation and dysfunction, as well as biventricular noncompaction,
        which fully recapitulated LVNC in patients.
      explanation: >-
        Noncompaction and LV dilation/dysfunction arise together in the same
        model and recapitulate the human phenotype. Directness is INDIRECT
        deliberately: the paper demonstrates that both follow from PRDM16
        loss and explains the left ventricle's selective vulnerability, but
        does not show that the compaction failure is what causes the
        dilation. Co-occurrence downstream of a shared cause is what this
        quote supports, not a demonstrated step between the two.

- name: Ventricular Conduction System Hyperplasia and Atrial-Fate Derepression
  biological_scale: TISSUE
  role: effector
  description: >-
    PRDM16 loss removes its suppression of master regulators of ventricular
    conduction and atrial cell fate within ventricular working
    cardiomyocytes. In cardiomyocyte-specific Prdm16-deletion mice this
    produces hyperplasia of the distal ventricular conduction system and
    abnormal postnatal electrophysiology, providing a mechanistic node
    upstream of arrhythmia and pre-excitation phenotypes that is distinct
    from (and additional to) arrhythmia risk driven by ventricular dilation
    and remodeling.
  locations:
  - preferred_term: central cardiac conduction system
    term:
      id: UBERON:2005074
      label: central cardiac conduction system
  biological_processes:
  - preferred_term: cardiac conduction system development
    term:
      id: GO:0003161
      label: cardiac conduction system development
  evidence:
  - reference: PMID:39304345
    reference_title: PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Myocardial loss of PRDM16 during development resulted in hyperplasia of
      the (distal) ventricular conduction system.
    explanation: >-
      Direct histological/molecular evidence that PRDM16 loss during cardiac
      development produces conduction-system hyperplasia, the structural
      substrate for a PRDM16-linked arrhythmia mechanism.
  - reference: PMID:39304345
    reference_title: PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      cardiomyocyte-specific deletion of Prdm16 during cardiac development
      results in contractile dysfunction and abnormal electrophysiology of
      the postnatal heart, resulting in premature death
    explanation: >-
      Confirms that cardiomyocyte-specific PRDM16 loss produces abnormal
      electrophysiology in vivo, consistent with an arrhythmogenic mechanism
      independent of remodeling-driven arrhythmia.
  downstream:
  - target: Arrhythmia and Ventricular Pre-excitation
    description: >-
      Ectopic/hyperplastic conduction-system tissue provides a structural
      substrate for accessory-pathway-type pre-excitation and other rhythm
      disturbances.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:39304345
      reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        cardiomyocyte-specific deletion of Prdm16 during cardiac development
        results in contractile dysfunction and abnormal electrophysiology of
        the postnatal heart
      explanation: >-
        The same study that reports ventricular conduction system
        hyperplasia also reports the resulting abnormal postnatal
        electrophysiology, supporting the step from ectopic conduction
        tissue to an arrhythmic substrate.
    - reference: PMID:39895316
      reference_title: "A rare genetic variant in PRDM16 is associated with Wolff-Parkinson-White syndrome with complex accessory pathway characteristics and left ventricular non-compaction cardiomyopathy."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        We report a 17-year-old girl with Wolff-Parkinson-White syndrome and
        left ventricular non-compaction cardiomyopathy due to a rare genetic
        variant in PR-domain containing protein 16.
      explanation: >-
        Human counterpart of the same edge: a PRDM16 variant carrier with
        LVNC presenting with ventricular pre-excitation, the
        accessory-pathway phenotype the conduction-system derepression node
        predicts.

- name: Left Ventricular Dilation and Systolic Dysfunction
  biological_scale: ORGANISM
  role: effector
  conforms_to: "cardiomyopathy_maladaptive_remodeling#Ventricular Remodeling"
  description: >-
    A subset of PRDM16 carriers develop left ventricular dilation and reduced
    systolic function, either accompanying noncompaction or, in some pedigrees
    and cardiac biopsy cohorts, as an apparently isolated dilated
    cardiomyopathy phenotype without prominent trabeculation, consistent with
    the MONDO definition of LVNC8 as a PRDM16-caused form of familial isolated
    dilated cardiomyopathy. Corresponds to the dismech-level phenotypes
    "Left Ventricular Noncompaction" and "Dilated Cardiomyopathy".
  evidence:
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In addition, in a series of cardiac biopsies from 131 individuals with
      DCM, we found 5 individuals with 4 previously unreported nonsynonymous
      variants in the coding region of PRDM16.
    explanation: >-
      Documents PRDM16 variants identified directly in a dilated
      cardiomyopathy biopsy cohort, supporting the DCM branch of the
      phenotype.
  - reference: PMID:34915728
    reference_title: PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      we also observed dramatic dilation that occurred only in LV of
      Prdm16cKO mice
    explanation: >-
      Mouse model shows LV-specific dilation is a direct consequence of
      cardiomyocyte PRDM16 loss, independent of noncompaction.
  downstream:
  - target: Congestive Heart Failure
    description: >-
      Progressive ventricular dilation and systolic dysfunction lead to
      symptomatic heart failure.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        One proband hosts a PRDM16-Q187X variant with left ventricular
        noncompaction cardiomyopathy and demonstrated infant-onset heart
        failure
      explanation: >-
        Documents progression to clinical heart failure in a PRDM16
        loss-of-function proband, the disease-specific instance of this
        edge.
    - reference: PMID:31959004
      reference_title: "Prognostic Significance of Left Ventricular Noncompaction: Systematic Review and Meta-Analysis of Observational Studies."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Meta-regression and subgroup analyses revealed that left ventricular
        ejection fraction, not the extent of left ventricular trabeculation,
        had an important influence on the variability of incidence rates.
      explanation: >-
        The discriminating evidence for this edge rather than for either node
        it joins: across LVNC cohorts it is ejection fraction, not the extent
        of trabeculation, that explains variation in event rates, which is
        what routes heart failure through the ventricular dysfunction node instead
        of directly off noncompaction. Directness is INDIRECT because the
        analysis pools LVNC of all causes rather than PRDM16 carriers.
  - target: Thromboembolic Risk
    description: >-
      Blood stasis in a dilated, hypokinetic, structurally abnormal
      ventricle predisposes to intracardiac thrombus formation and embolism.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:25443708
      reference_title: "Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?"
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: OTHER
      snippet: >-
        Complications with LVNC include heart failure, arrhythmias including
        sudden cardiac death, and systemic embolic events
      explanation: >-
        Lists systemic embolic events among the complications of LVNC.
        Directness is INDIRECT: this establishes thromboembolism as a
        downstream complication of the cardiomyopathy without isolating
        reduced systolic function as its cause, and one PRDM16-positive
        thromboembolic event in the cited paediatric series occurred without
        worsening heart failure. Evidence source is OTHER because this
        sentence is the review's own narrative summary rather than a result
        it reports; the cohort figures quoted elsewhere from this same paper
        are graded HUMAN_CLINICAL.
    - reference: PMID:31959004
      reference_title: "Prognostic Significance of Left Ventricular Noncompaction: Systematic Review and Meta-Analysis of Observational Studies."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Meta-regression and subgroup analyses revealed that left ventricular
        ejection fraction, not the extent of left ventricular trabeculation,
        had an important influence on the variability of incidence rates.
      explanation: >-
        The discriminating evidence for this edge rather than for either node
        it joins: across LVNC cohorts it is ejection fraction, not the extent
        of trabeculation, that explains variation in event rates, which is
        what routes thromboembolism through the ventricular dysfunction node instead
        of directly off noncompaction. Directness is INDIRECT because the
        analysis pools LVNC of all causes rather than PRDM16 carriers.
  - target: Arrhythmia and Ventricular Pre-excitation
    description: >-
      Ventricular dilation and remodeling independently increase
      arrhythmogenic risk, in addition to the conduction-system substrate
      described above.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:25443708
      reference_title: "Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?"
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Ventricular tachyarrhythmias have been reported in up to 47% of
        symptomatic patients referred to a tertiary referral center, and SCD
        has been reported in 13% to 18% of (mostly adult) patients with
        LVNC.
      explanation: >-
        Quantifies the ventricular arrhythmia and sudden-death burden in
        symptomatic LVNC cohorts, which is reported cohort data rather than
        review commentary, hence HUMAN_CLINICAL. Directness is INDIRECT: the
        cohorts are defined by being symptomatic rather than by measured
        systolic
        dysfunction, so the attribution to ventricular dilation and
        dysfunction is an inference.
    - reference: PMID:31959004
      reference_title: "Prognostic Significance of Left Ventricular Noncompaction: Systematic Review and Meta-Analysis of Observational Studies."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Meta-regression and subgroup analyses revealed that left ventricular
        ejection fraction, not the extent of left ventricular trabeculation,
        had an important influence on the variability of incidence rates.
      explanation: >-
        The discriminating evidence for this edge rather than for either node
        it joins: across LVNC cohorts it is ejection fraction, not the extent
        of trabeculation, that explains variation in event rates, which is
        what routes arrhythmia through the ventricular dysfunction node
        instead of directly off noncompaction. Directness is INDIRECT because
        the analysis pools LVNC of all causes rather than PRDM16 carriers.

- name: Congestive Heart Failure
  biological_scale: ORGANISM
  role: effector
  conforms_to: "cardiomyopathy_maladaptive_remodeling#Structural Cardiac Impairment and Heart Failure"
  description: >-
    Affected individuals progress to congestive heart failure, often with
    early or infant onset in the more severe pediatric cases. A single-center
    pediatric LVNC cohort documented heart failure as an adverse outcome in a
    PRDM16-positive patient.
  evidence:
  - reference: PMID:38113297
    reference_title: Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      One proband hosts a PRDM16-Q187X variant with left ventricular
      noncompaction cardiomyopathy and demonstrated infant-onset heart
      failure, which was selected for further study.
    explanation: >-
      Documents infant-onset heart failure as a clinical outcome directly
      linked to a PRDM16 loss-of-function variant.
  - reference: PMID:35893073
    reference_title: Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children-A Single Reference Center Experience.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Among those who developed symptoms of HF (LVEF reduction and LV
      enlargement) were patients P9 (novel pathogenic PRDM16 complex
      rearrangement c.1286_1289delinsTTGCACTT p.(Gly429Valfs*176))
    explanation: >-
      A pediatric LVNC cohort documents heart failure as an adverse outcome
      in a PRDM16-positive patient.
  - reference: PMID:31959004
    reference_title: "Prognostic Significance of Left Ventricular Noncompaction: Systematic Review and Meta-Analysis of Observational Studies."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The incidence rates of all-cause mortality, stroke and systemic
      emboli, heart failure admission, cardiac transplantation,
      ventricular arrhythmias, and cardiac device implantation were 2.16,
      1.54, 3.53, 1.24, 2.17, and 2.66, respectively, per 100
      person-years.
    explanation: >-
      Gives the pooled rate of heart failure admission in LVNC, 3.53 per
      100 person-years and the highest of the six event rates reported,
      which sizes this node against the other downstream consequences.
      Directness is INDIRECT because the pooled cohorts are LVNC of all
      causes rather than PRDM16 carriers.

- name: Arrhythmia and Ventricular Pre-excitation
  biological_scale: ORGANISM
  role: effector
  description: >-
    PRDM16-associated cardiomyopathy carries an increased risk of cardiac
    arrhythmia. Beyond the remodeling-driven arrhythmia risk shared with
    other dilated/noncompaction cardiomyopathies, one reported adolescent
    carrier presented with Wolff-Parkinson-White syndrome (ventricular
    pre-excitation via a complex accessory pathway), mechanistically
    consistent with the conduction-system-hyperplasia node above.
  evidence:
  - reference: PMID:39895316
    reference_title: A rare genetic variant in PRDM16 is associated with Wolff-Parkinson-White syndrome with complex accessory pathway characteristics and left ventricular non-compaction cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report a 17-year-old girl with Wolff – Parkinson– White syndrome and
      left ventricular non-compaction cardiomyopathy due to a rare genetic
      variant in PR-domain containing protein 16.
    explanation: >-
      Case report documents ventricular pre-excitation (Wolff-Parkinson-White
      syndrome) co-occurring with LVNC in a PRDM16 variant carrier.
  - reference: PMID:31959004
    reference_title: "Prognostic Significance of Left Ventricular Noncompaction: Systematic Review and Meta-Analysis of Observational Studies."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The incidence rates of all-cause mortality, stroke and systemic
      emboli, heart failure admission, cardiac transplantation,
      ventricular arrhythmias, and cardiac device implantation were 2.16,
      1.54, 3.53, 1.24, 2.17, and 2.66, respectively, per 100
      person-years.
    explanation: >-
      Gives the pooled ventricular arrhythmia rate in LVNC, 2.17 per 100
      person-years, alongside a cardiac device implantation rate of 2.66.
      Directness is INDIRECT: the pooled cohorts are LVNC of all causes,
      and the meta-analysis reports ventricular arrhythmia generally
      rather than the accessory-pathway pre-excitation that also names
      this node.

- name: Thromboembolic Risk
  biological_scale: ORGANISM
  role: effector
  description: >-
    Thromboembolic complications, consistent with stasis in a dilated,
    hypokinetic, and structurally abnormal ventricle, have been documented in
    PRDM16-positive patients. A single-center pediatric LVNC cohort found two
    PRDM16-positive patients experienced adverse events (heart failure in
    one, a thromboembolic event in the other).
  evidence:
  - reference: PMID:35893073
    reference_title: Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children-A Single Reference Center Experience.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A thromboembolic event, without increasing symptoms of HF, was noted in
      P8 (novel PRDM16 pathogenic c.1336G>T p.(Glu446*) variant)
    explanation: >-
      Documents a thromboembolic event as an adverse clinical outcome in a
      pediatric patient with a novel pathogenic PRDM16 variant.

  - reference: PMID:31959004
    reference_title: "Prognostic Significance of Left Ventricular Noncompaction: Systematic Review and Meta-Analysis of Observational Studies."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The incidence rates of all-cause mortality, stroke and systemic
      emboli, heart failure admission, cardiac transplantation,
      ventricular arrhythmias, and cardiac device implantation were 2.16,
      1.54, 3.53, 1.24, 2.17, and 2.66, respectively, per 100
      person-years.
    explanation: >-
      Gives the pooled rate of stroke and systemic emboli in LVNC, 1.54
      per 100 person-years. Directness is INDIRECT because the pooled
      cohorts are LVNC of all causes rather than PRDM16 carriers.

phenotypes:
- name: Left Ventricular Noncompaction
  category: Cardiovascular
  description: >-
    Excessive left ventricular trabeculation with deep intertrabecular
    recesses over a thinned compacted myocardial layer, the structural
    hallmark of the noncompaction branch of the PRDM16 phenotype.
  phenotype_term:
    preferred_term: Left ventricular noncompaction
    term:
      id: HP:0030682
      label: Left ventricular noncompaction
  evidence:
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Resequencing of PRDM16 in a cohort of 75 nonsyndromic individuals with
      LVNC detected three mutations, including one truncation mutant, one
      frameshift null mutation, and a single missense mutant.
    explanation: >-
      Establishes left ventricular noncompaction as a clinical phenotype
      directly associated with PRDM16 variants.

- name: Dilated Cardiomyopathy
  category: Cardiovascular
  description: >-
    Ventricular dilation with impaired systolic function, the phenotype MONDO
    uses to define LVNC8 ("familial isolated dilated cardiomyopathy...caused by
    ...PRDM16"), occurring either with or without accompanying noncompaction.
  phenotype_term:
    preferred_term: Dilated cardiomyopathy
    term:
      id: HP:0001644
      label: Dilated cardiomyopathy
  evidence:
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In addition, in a series of cardiac biopsies from 131 individuals with
      DCM, we found 5 individuals with 4 previously unreported nonsynonymous
      variants in the coding region of PRDM16.
    explanation: >-
      Documents dilated cardiomyopathy as a clinical phenotype directly
      associated with PRDM16 variants, independent of a noncompaction
      diagnosis.

- name: Congestive Heart Failure
  category: Cardiovascular
  frequency: FREQUENT
  description: >-
    Symptomatic heart failure, sometimes with infant onset in severe pediatric
    cases, is a common outcome of PRDM16-associated cardiomyopathy.
  phenotype_term:
    preferred_term: Congestive heart failure
    term:
      id: HP:0001635
      label: Congestive heart failure
  evidence:
  - reference: PMID:38113297
    reference_title: Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      One proband hosts a PRDM16-Q187X variant with left ventricular
      noncompaction cardiomyopathy and demonstrated infant-onset heart
      failure, which was selected for further study.
    explanation: >-
      Confirms heart failure, with infant onset in the severe pediatric case
      reported, as a clinical feature of PRDM16-associated cardiomyopathy.

- name: Wolff-Parkinson-White Syndrome
  category: Cardiovascular
  description: >-
    Ventricular pre-excitation via a complex accessory conduction pathway,
    reported in one adolescent PRDM16-LVNC carrier and mechanistically
    consistent with the PRDM16-dependent conduction-system-hyperplasia node
    (PMID:39304345). The specific Wolff-Parkinson-White term is used here
    rather than the generic arrhythmia term because the description and the
    sole supporting evidence are specifically about this syndrome.
  phenotype_term:
    preferred_term: Wolff-Parkinson-White syndrome
    term:
      id: HP:0001716
      label: Wolff-Parkinson-White syndrome
  evidence:
  - reference: PMID:39895316
    reference_title: A rare genetic variant in PRDM16 is associated with Wolff-Parkinson-White syndrome with complex accessory pathway characteristics and left ventricular non-compaction cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report a 17-year-old girl with Wolff – Parkinson– White syndrome and
      left ventricular non-compaction cardiomyopathy due to a rare genetic
      variant in PR-domain containing protein 16.
    explanation: >-
      Case report documents Wolff-Parkinson-White syndrome co-occurring with
      LVNC in a PRDM16 variant carrier.

- name: Thromboembolic Event
  category: Cardiovascular
  description: >-
    Thromboembolic complications, consistent with stasis in a dilated,
    hypokinetic, and structurally abnormal ventricle, have been documented in
    PRDM16-positive patients.
  phenotype_term:
    preferred_term: Thromboembolism
    term:
      id: HP:0001907
      label: Thromboembolism
  evidence:
  - reference: PMID:35893073
    reference_title: Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children-A Single Reference Center Experience.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A thromboembolic event, without increasing symptoms of HF, was noted in
      P8 (novel PRDM16 pathogenic c.1336G>T p.(Glu446*) variant)
    explanation: >-
      Documents a thromboembolic event as an adverse clinical outcome in a
      pediatric patient with a novel pathogenic PRDM16 variant.

- name: Myocardial Fibrosis
  category: Cardiovascular
  description: >-
    Heightened myocardial fibrosis has been reported in a heterozygous
    Prdm16-Q187X knock-in mouse model, and endocardial fibroelastosis was
    reported in the fetal-onset human case, mirroring the fibrotic component
    of the ventricular remodeling described above.
  phenotype_term:
    preferred_term: Myocardial fibrosis
    term:
      id: HP:0001685
      label: Myocardial fibrosis
  evidence:
  - reference: PMID:38113297
    reference_title: Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller
      ventricular dimensions, heightened fibrosis, and age-dependent loss of
      TGF-β expression.
    explanation: >-
      Documents heightened myocardial fibrosis as a feature of the
      heterozygous PRDM16-Q187X mouse model.

- name: Fetal-Onset Cardiomegaly and Hydrops
  category: Cardiovascular
  frequency: VERY_RARE
  description: >-
    The most severe reported presentation is prenatal: a third-trimester fetus
    with a de novo PRDM16 nonsense variant showed hydrops, hydramnios, and an
    expanded hypokinetic heart with cardiomegaly and endocardial
    fibroelastosis, leading to termination of pregnancy.
  phenotype_term:
    preferred_term: Nonimmune hydrops fetalis
    term:
      id: HP:0001790
      label: Nonimmune hydrops fetalis
  evidence:
  - reference: PMID:31965688
    reference_title: "Cardiomyopathy due to PRDM16 mutation: First description of a fetal presentation, with possible modifier genes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The third-trimester obstetric ultrasound revealed a hydropic fetus with
      hydramnios and expanded hypokinetic heart. After termination of
      pregnancy, foetopathology showed a eutrophic fetus with isolated
      cardiomegaly.
    explanation: >-
      First reported fetal presentation of PRDM16-associated cardiomyopathy,
      establishing hydrops fetalis and cardiomegaly as a rare but documented
      severe end of the phenotypic spectrum.

genetic:
- name: PRDM16
  gene_term:
    preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  association: Pathogenic Variants
  case_fractions:
  - population: Single-center pediatric LVNC cohort (Poland)
    case_fraction_percent: 12.5
    cohort_size: 16
    notes: >-
      2 of 16 patients with a confirmed molecular defect in a pediatric LVNC
      referral cohort carried a PRDM16 variant, tied with MYH7 as the second
      most frequent gene after HCN4.
    evidence:
    - reference: PMID:35893073
      reference_title: Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children-A Single Reference Center Experience.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The most frequent defects in our cohort were found in the genes HCN4
        (n = 4), MYH7 (n = 2) and PRDM16 (n = 2).
      explanation: >-
        Quantifies the PRDM16 share of molecularly confirmed cases in a
        pediatric LVNC cohort.
  - population: Large multicenter LVNC rare-variant case-control cohort vs. gnomAD population controls
    case_fraction_percent: 1.35
    notes: >-
      PRDM16 truncating variants were significantly enriched in a large LVNC
      case-control rare-variant association study relative to gnomAD
      population controls (p = 4.0E-12), a far larger and better-controlled
      estimate than the single-center pediatric cohort above; the two are
      recorded separately because they measure different populations
      (pediatric referral cohort vs. multicenter case-control).
    evidence:
    - reference: PMID:38019448
      reference_title: "The Trouble with Trabeculation: How Genetics Can Help to Unravel a Complex and Controversial Phenotype."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        population controls, i.e. no enrichment was observed in similar
        analyses with HCM or DCM cohorts ... These were truncating variants
        in ... PRDM16 (1.35% vs 0.006%,
      explanation: >-
        Reports the PRDM16 truncating-variant case frequency (1.35% of LVNC
        cases vs 0.006% in gnomAD controls) from a large rare-variant
        association study cited in a 2023 review of LVNC genetics.
  notes: >-
    ClinGen classifies the PRDM16-dilated cardiomyopathy gene-disease
    relationship as Strong with autosomal dominant inheritance (see
    Dilated_Cardiomyopathy.yaml for the shared ClinGen assertion). A
    contemporary review reports a variant-class genotype-phenotype
    correlation: missense variants track with DCM, nonsense/frameshift
    (loss-of-function) variants track with LVNC, and PRDM16 is predicted to
    be highly loss-of-function-intolerant (see the discussions entry above
    and the PRDM16 Loss-of-Function Variant pathophysiology node).
  evidence:
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PRDM16 has not previously been associated with cardiac disease but is
      localized in the nuclei of cardiomyocytes throughout murine and human
      development and in the adult heart.
    explanation: >-
      Establishes PRDM16 as the founding causal gene for this entity and
      documents its cardiomyocyte nuclear localization.
  - reference: CGGV:assertion_c0a3445a-5bb0-4d77-a4f0-5b7cfceb837f-2025-05-30T160000.000Z
    reference_title: "PRDM16 / dilated cardiomyopathy (Strong)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "PRDM16 | HGNC:14000 | dilated cardiomyopathy | MONDO:0005021 | AD | Strong"
    explanation: >-
      ClinGen classifies the PRDM16-dilated cardiomyopathy gene-disease
      relationship as strong with autosomal dominant inheritance.

inheritance:
- name: Autosomal Dominant
  description: >-
    Reported PRDM16 cardiomyopathy cases follow autosomal dominant
    transmission of a heterozygous variant; several cases, including the
    fetal presentation and one of two pediatric probands in the TGF-beta
    mechanistic study, arose de novo.
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  evidence:
  - reference: CGGV:assertion_c0a3445a-5bb0-4d77-a4f0-5b7cfceb837f-2025-05-30T160000.000Z
    reference_title: "PRDM16 / dilated cardiomyopathy (Strong)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "PRDM16 | HGNC:14000 | dilated cardiomyopathy | MONDO:0005021 | AD | Strong"
    explanation: >-
      ClinGen Hereditary Cardiovascular Disease GCEP records autosomal
      dominant inheritance for the PRDM16-dilated cardiomyopathy relationship
      with Strong clinical validity.
  - reference: PMID:31965688
    reference_title: "Cardiomyopathy due to PRDM16 mutation: First description of a fetal presentation, with possible modifier genes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Exome sequencing (ES) identified a de novo unreported p.(Gln353*)
      heterozygous nonsense variant in PRDM16.
    explanation: >-
      Documents a de novo heterozygous PRDM16 nonsense variant, consistent
      with autosomal dominant, often sporadic, transmission.

diagnosis:
- name: Echocardiography
  description: >-
    First-line imaging modality for LVNC. The most widely used echocardiographic
    diagnostic criterion is a noncompacted-to-compacted (NC/C) myocardial
    thickness ratio greater than 2.0 measured at end-systole, though this
    threshold carries substantial interobserver and intraobserver variability
    and is not LVNC8-specific.
  diagnosis_term:
    preferred_term: echocardiography
    term:
      id: NCIT:C16525
      label: Echocardiography Test
  evidence:
  - reference: PMID:25443708
    reference_title: "Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      the most important echocardiographic criterion remains the ratio of
      noncompacted/compacted >2.0 in end-systole
    explanation: >-
      States the quantitative echocardiographic NC/C >2.0 criterion used to
      diagnose LVNC. Evidence source is OTHER because this is a review.

- name: Cardiac Magnetic Resonance Imaging
  description: >-
    CMR gives a 3-dimensional dataset that better resolves trabecular
    architecture than echocardiography. A noncompacted-to-compacted ratio
    greater than 2.3 measured at end-diastole on CMR is the commonly cited
    diagnostic cutoff, and CMR additionally assesses fibrosis via late
    gadolinium enhancement. Neither the echocardiographic nor the CMR
    threshold is sufficiently specific in isolation.
  diagnosis_term:
    preferred_term: cardiac magnetic resonance imaging
    term:
      id: NCIT:C16809
      label: Magnetic Resonance Imaging
  evidence:
  - reference: PMID:25443708
    reference_title: "Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      A noncompacted/compacted ratio >2.3 on CMR is considered the cutoff for
      LVNC diagnosis
    explanation: >-
      States the quantitative CMR NC/C >2.3 criterion used to diagnose LVNC.
      Evidence source is OTHER because this is a review.

- name: Natriuretic Peptide Measurement
  description: >-
    BNP/NT-proBNP assesses heart failure severity and cardiomyocyte stretch
    but is not diagnostic of LVNC8 specifically. Heterozygous Prdm16
    mutant mice show elevated plasma BNP, supporting its use as a marker of
    cardiac stretch/dysfunction downstream of PRDM16 loss rather than a
    disease-specific biomarker.
  diagnosis_term:
    preferred_term: brain natriuretic peptide measurement
    term:
      id: NCIT:C74735
      label: Brain Natriuretic Peptide Measurement
  evidence:
  - reference: PMID:37842925
    reference_title: Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      We found an elevation of plasma levels of brain natriuretic peptide
      (Bnp) in both sexes, indicating cardiomyocyte stretch with impaired
      systolic and possibly diastolic LV dysfunction
    explanation: >-
      Mouse-model evidence that BNP is elevated downstream of PRDM16 loss;
      PARTIAL because this is a general heart-failure-stretch biomarker in a
      mouse model, not an LVNC8-specific human diagnostic marker.

- name: Cardiomyopathy Multigene Panel Sequencing with Copy-Number Analysis
  description: >-
    The confirmatory test is a clinically curated cardiomyopathy gene panel
    including PRDM16. Copy-number analysis (chromosomal microarray) is
    important alongside sequencing specifically to distinguish an intragenic
    PRDM16 variant (LVNC8) from a 1p36 deletion spanning PRDM16 (1p36
    deletion syndrome), since the original mapping of the PRDM16 cardiac
    critical region was itself done by comparative genomic hybridization
    delineating the terminal 1p36 deletion interval.
  diagnosis_term:
    preferred_term: cardiomyopathy multigene panel sequencing with copy-number analysis
    term:
      id: NCIT:C15709
      label: Genetic Testing
  evidence:
  - reference: PMID:20301486
    reference_title: Dilated Cardiomyopathy Overview.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Provide the evaluation strategy of a proband with nonsyndromic DCM
    explanation: >-
      The GeneReviews DCM overview exists to supply this proband evaluation
      strategy, of which gene-panel and copy-number testing is a component.
      Evidence source is OTHER because GeneReviews is an expert-authored
      review resource.
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we identified a minimal deletion for the cardiomyopathy associated with
      1p36del syndrome that included only the terminal 14 exons of the
      transcription factor PRDM16
    explanation: >-
      Comparative genomic hybridization (the copy-number method) was how the
      PRDM16 cardiac critical region within the 1p36 deletion was originally
      delineated, supporting copy-number analysis as the tool that
      distinguishes a 1p36 deletion from an intragenic PRDM16 variant.

differential_diagnoses:
- name: Left ventricular noncompaction (polygenic umbrella)
  description: >-
    Isolated LVNC of other or undetermined genetic cause, including sarcomeric
    (MYH7, ACTN2), cytoskeletal (NRAP), and mitochondrial (TAFAZZIN) etiologies
    modeled in the umbrella dismech entry.
  distinguishing_features:
  - A confirmed PRDM16 loss-of-function variant identifies LVNC8 specifically, versus the broader genetically heterogeneous LVNC umbrella.
  - Truncating PRDM16 (along with MYH7 and ACTN2) variants show LVNC-specific enrichment in large rare-variant studies, unlike genes shared broadly across DCM/HCM/LVNC.
  disease_term:
    preferred_term: left ventricular noncompaction
    term:
      id: MONDO:0018901
      label: left ventricular noncompaction
  evidence:
  - reference: PMID:33500567
    reference_title: Systematic large-scale assessment of the genetic architecture of left ventricular noncompaction reveals diverse etiologies.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In contrast, truncating variants in MYH7, ACTN2, and PRDM16 were uniquely
      associated with LVNC and may reflect a distinct LVNC etiology.
    explanation: >-
      Directly distinguishes PRDM16 (and MYH7/ACTN2) from the broader,
      LVNC-associated gene set as having LVNC-specific rare-variant
      enrichment.

- name: 1p36 deletion syndrome
  description: >-
    A contiguous-gene deletion syndrome of the terminal short arm of
    chromosome 1 that includes PRDM16 within its cardiomyopathy critical
    region, together with craniofacial anomalies, intellectual disability,
    seizures, and other syndromic features not present in isolated LVNC8.
  distinguishing_features:
  - 1p36 deletion syndrome is a multigene contiguous deletion with extracardiac syndromic features; LVNC8 is a nonsyndromic, single-gene PRDM16 point-mutation or small-indel disorder confined to the cardiac phenotype.
  - Array CGH or chromosomal microarray identifying a terminal 1p36 deletion spanning PRDM16 (rather than an intragenic PRDM16 variant) indicates 1p36 deletion syndrome rather than LVNC8.
  evidence:
  - reference: PMID:23768516
    reference_title: Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we identified a minimal deletion for the cardiomyopathy associated with
      1p36del syndrome that included only the terminal 14 exons of the
      transcription factor PRDM16
    explanation: >-
      Establishes PRDM16 as the cardiomyopathy-critical gene within the larger
      1p36 deletion syndrome region, distinguishing the contiguous-gene
      syndrome from isolated PRDM16 point-mutation disease.

treatments:
- name: Guideline-Directed Heart Failure Pharmacotherapy
  description: >-
    Standard heart failure pharmacotherapy (e.g., ACE inhibitors/ARBs or
    ARNI, beta-blockers, mineralocorticoid receptor antagonists, SGLT2
    inhibitors) is used to manage systolic dysfunction in PRDM16-associated
    cardiomyopathy. There is no PRDM16- or LVNC8-specific pharmacotherapy;
    management follows the general phenotype-based approach used for LVNC and
    DCM.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
  evidence:
  - reference: PMID:25443708
    reference_title: "Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Currently, there are no specific treatments for LVNC. Depending on the
      phenotype, patients are managed according to their clinical needs and
      corresponding guidelines (e.g., for congestive heart failure,
      arrhythmias).
    explanation: >-
      States directly that LVNC (and by extension LVNC8) has no
      disease-specific pharmacotherapy and is managed with standard
      phenotype-based guideline therapy. Evidence source is OTHER because
      this is a review.

- name: Implantable Cardioverter-Defibrillator Placement
  description: >-
    ICD implantation is considered for PRDM16-associated cardiomyopathy
    patients at risk of ventricular arrhythmia and sudden cardiac death,
    following conventional primary/secondary-prevention criteria for
    LVNC/DCM rather than a PRDM16-specific indication.
  therapeutic_modality: DEVICE
  treatment_term:
    preferred_term: Implantable Cardioverter-Defibrillator Placement
    term:
      id: NCIT:C80435
      label: Implantable Cardioverter-Defibrillator Placement
  evidence:
  - reference: PMID:25443708
    reference_title: "Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In 30 patients with LVNC who underwent implantable cardioverter
      defibrillator (ICD) implantation for secondary or primary prevention,
      11 patients (37%) had appropriate ICD therapies in a mean follow-up
      period of 40 ± 34 months
    explanation: >-
      Reports outcome data for ICD implantation specifically in LVNC
      patients (37% received appropriate therapy), directly supporting ICD
      placement as a real intervention with documented efficacy signal in
      this cardiomyopathy.

- name: Anticoagulation for Thromboembolic Risk
  description: >-
    Anticoagulant therapy is considered in patients with reduced systolic
    function or documented thromboembolic events, given the thromboembolic
    complications reported in PRDM16-positive LVNC patients. Routine
    anticoagulation for isolated trabeculation with normal ventricular
    function remains debated.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: anticoagulant agent
      term:
        id: NCIT:C263
        label: Anticoagulant Agent
  evidence:
  - reference: PMID:25443708
    reference_title: "Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Oral anticoagulation is a debated issue in subjects with normal LV
      function and absence of LV hypertrophy: patients are either treated on
      the basis of the phenotype (oral anticoagulation given independently on
      arrhythmias or LV dysfunction for primary prevention of embolic
      episodes) or in the presence of LV dysfunction, arrhythmias, prior
      embolic events, or proven atrial or ventricular thrombi.
    explanation: >-
      States the clinical indications for oral anticoagulation in LVNC
      directly. Evidence source is OTHER because this is a review.
  - reference: PMID:35893073
    reference_title: Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children-A Single Reference Center Experience.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A thromboembolic event, without increasing symptoms of HF, was noted in
      P8 (novel PRDM16 pathogenic c.1336G>T p.(Glu446*) variant)
    explanation: >-
      Documents a thromboembolic complication in a PRDM16-positive patient,
      the clinical indication anticoagulation is intended to prevent.

- name: Cardiac Transplantation
  description: >-
    Heart transplantation is the definitive treatment for end-stage heart
    failure in severe PRDM16-associated cardiomyopathy, following standard
    advanced-heart-failure criteria rather than a PRDM16-specific one. A
    multi-institutional 1p36 deletion cohort does show that PRDM16 deletion
    carries an increased risk of a combined endpoint of death, transplant or
    ventricular assist device, so the genotype does bear on how often this
    endpoint is reached; that cohort is the contiguous-gene-deletion context
    rather than nonsyndromic LVNC8. Rates at the level of LVNC as a whole are
    recorded alongside.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: Organ Transplantation
    term:
      id: NCIT:C15289
      label: Organ Transplantation
  evidence:
  - reference: PMID:35893073
    reference_title: Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children-A Single Reference Center Experience.
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mechanical circulatory support (LVAD) was implanted in a patient with
      extremely low LV systolic function; he was qualified for heart
      transplant, but died while waiting for a heart transplant.
    explanation: >-
      Documents escalation to mechanical circulatory support and transplant
      candidacy as the real endpoint of end-stage systolic failure in a
      paediatric LVNC cohort. Directness is INDIRECT because the transplant
      candidate in this series is not one of its two PRDM16-positive patients,
      so this supports transplantation as the LVNC endpoint rather than as a
      PRDM16-specific indication.
  - reference: PMID:37395136
    reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PRDM16 deletion was associated with increased risk of death, cardiac
      transplant, or ventricular assist device (P=0.04).
    explanation: >-
      Ties PRDM16 loss itself to the transplant and mechanical-support
      endpoint, against a within-syndrome comparison group whose deletion
      spares PRDM16. Directness is INDIRECT on two counts: the cohort is 1p36
      deletion syndrome rather than nonsyndromic LVNC8, and the endpoint is
      combined with death and ventricular assist device, so it does not
      report a transplant rate on its own.
  - reference: PMID:39420976
    reference_title: "Prevalence, Clinical Manifestations, and Adverse Outcomes of Left Ventricular Noncompaction in Adults: A Systematic Review and Meta-Analysis."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mortality and heart transplantation rates were 12% and 7%, respectively.
    explanation: >-
      Gives the pooled adult transplantation rate for LVNC, which sizes how
      often this treatment is reached. Directness is INDIRECT because the
      pooled cohorts are LVNC of all causes rather than PRDM16 carriers.

- name: Cascade Genetic Testing and Counseling
  description: >-
    Genetic testing for the proband's PRDM16 variant and cascade testing of
    at-risk relatives is recommended given autosomal dominant transmission,
    given that a subset of first-degree relatives of PRDM16 probands may carry
    the variant.
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:31965688
    reference_title: "Cardiomyopathy due to PRDM16 mutation: First description of a fetal presentation, with possible modifier genes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Exome sequencing (ES) identified a de novo unreported p.(Gln353*)
      heterozygous nonsense variant in PRDM16.
    explanation: >-
      Documents molecular genetic testing (exome sequencing) as the diagnostic
      route to identifying a causal PRDM16 variant, supporting genetic
      testing and counseling as a management step.
  - reference: PMID:20301486
    reference_title: Dilated Cardiomyopathy Overview.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Provide a basic view of genetic risk assessment of at-risk asymptomatic
      relatives of a proband with DCM to inform cardiac surveillance and allow
      early detection and treatment of DCM to improve long-term outcome.
    explanation: >-
      The GeneReviews DCM overview frames genetic risk assessment of at-risk
      asymptomatic relatives, with cardiac surveillance for early detection,
      as the purpose of cascade evaluation — precisely this treatment.
      Evidence source is OTHER because GeneReviews is an expert-authored
      review resource.

clinical_trials:
- name: NCT06024759
  phase: NOT_APPLICABLE
  status: RECRUITING
  description: >-
    Ten-year observational registry following patients with left ventricular
    noncompaction to identify predictors of adverse outcome. Its stated
    questions map onto this entry's downstream nodes almost directly: whether
    genotype predicts ventricular arrhythmia risk, what determines left
    ventricular dysfunction in LVNC, and which rhythm markers predict ICD
    implantation. Not PRDM16-specific, but it is the study most likely to
    produce genotype-stratified arrhythmia risk for genes including PRDM16.
    Phase is NOT_APPLICABLE because this is an observational registry rather
    than an interventional trial.
  target_phenotypes:
  - preferred_term: Ventricular arrhythmia
    term:
      id: HP:0004308
      label: Ventricular arrhythmia
  - preferred_term: Left ventricular noncompaction
    term:
      id: HP:0030682
      label: Left ventricular noncompaction
  evidence:
  - reference: clinicaltrials:NCT06024759
    reference_title: Long Term Registry of Patients With Left Ventricular Non-Compaction and Predictors of Adverse Outcomes
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Are there any genetic mutations that impact the risk of LVNC patients
      developing ventricular arrhythmias?
    explanation: >-
      The registry's primary question is whether genotype stratifies
      arrhythmia risk in LVNC, which is the open question this entry's
      arrhythmia node leaves for PRDM16 carriers.
- name: NCT03572569
  phase: NOT_APPLICABLE
  status: UNKNOWN
  description: >-
    RIKADA, a prospective family-based study of children and adolescents with
    primary cardiomyopathy, screening probands and first-degree relatives
    clinically and genetically to support risk stratification. Relevant here
    as the paediatric counterpart of the cascade-testing treatment curated in
    this entry, though it covers primary cardiomyopathy broadly rather than
    LVNC or PRDM16 specifically. Registry status is UNKNOWN as of this
    curation, with recruiting the last reported state; phase is
    NOT_APPLICABLE because it is observational.
  evidence:
  - reference: clinicaltrials:NCT03572569
    reference_title: Risk Stratification in Children and Adolescents With Primary Cardiomyopathy
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      RIKADA is a prospective study performing systematic family screening
      including clinical and genetic testing in pediatric patients with
      primary cardiomyopathy and their first-degree relatives with the aim to
      facilitate risk stratification.
    explanation: >-
      Describes systematic family screening with genetic testing in paediatric
      cardiomyopathy, the practice this entry curates as cascade testing.
      Directness is INDIRECT because the study population is primary
      cardiomyopathy generally, not LVNC or PRDM16 carriers.

prevalence:
- population: Molecularly confirmed PRDM16-associated LVNC (LVNC8)
  measure_type: UNKNOWN
  prevalence_class: NOT_YET_DOCUMENTED
  notes: >-
    No prevalence or incidence estimate exists for molecularly confirmed
    LVNC8, so no band or rate is asserted for this entity. Two published
    figures bound it from either side and are recorded here with their
    evidence rather than as structured rates, because neither has LVNC8 as
    its denominator and a structured band would misreport this rare Mendelian
    entity. Upper bound: pooled adult prevalence of the LVNC phenotype from
    all causes is 0.5%, of which PRDM16 explains only a fraction; the same
    review reports a 1.3% detection rate by cardiovascular magnetic
    resonance, which is a modality effect rather than a second estimate and
    shows how strongly LVNC ascertainment depends on imaging method and
    criteria. Penetrance, not prevalence: among 134 individuals with 1p36
    deletion syndrome, 29.1% of those whose deletion removed PRDM16 developed
    cardiomyopathy against 10.8% of those whose deletion spared it; the
    retrospective arm alone (n=71) gave 34.5% versus 7.7% without reaching
    significance. That is the contiguous-gene-deletion context and other
    genes in the interval may modify the risk, so it is not the penetrance of
    a nonsyndromic PRDM16 variant.
  evidence:
  - reference: PMID:39420976
    reference_title: "Prevalence, Clinical Manifestations, and Adverse Outcomes of Left Ventricular Noncompaction in Adults: A Systematic Review and Meta-Analysis."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The study showed a prevalence of LVNC of 0.5%, with cardiovascular
      magnetic resonance outperforming echocardiography in diagnosis with a
      detection rate of 1.3%.
    explanation: >-
      Supplies the upper bound recorded above. Directness is INDIRECT because
      the pooled denominator is adults screened for the LVNC phenotype from
      all causes, not PRDM16 carriers, so it bounds LVNC8 without estimating
      it.
  - reference: PMID:37395136
    reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In the combined retrospective and systematic review cohort (n=134),
      PRDM16 deletion-associated cardiomyopathy risk was recapitulated and
      significant (29.1% versus 10.8%, P=0.03).
    explanation: >-
      Supplies the penetrance figure recorded above, isolating PRDM16's
      contribution against a within-syndrome comparison group whose deletion
      spares the gene. Directness is INDIRECT because the cohort is 1p36
      deletion syndrome rather than nonsyndromic LVNC8, and because
      cardiomyopathy incidence in an at-risk genotype is penetrance, not the
      population prevalence this slot otherwise reports.
  - reference: PMID:37395136
    reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Among individuals with PRDM16 deleted, 34.5% developed cardiomyopathy
      versus 7.7% of individuals with PRDM16 not deleted (P=0.1).
    explanation: >-
      The retrospective arm considered alone, recorded because its effect
      size is larger than the pooled figure while its P value does not reach
      significance at this sample size. Directness is INDIRECT for the same
      reasons as the pooled figure above.

datasets:
- accession: geo:GSE307782
  title: PRDM16 Modulates Aspects of Cell-Cycle Dynamics and Maturation in Human iPSC-Derived Cardiomyocytes
  data_type: BULK_RNA_SEQ
  organism:
    preferred_term: human
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  evidence:
  - reference: GEO:GSE307782
    reference_title: "PRDM16 Modulates Aspects of Cell-Cycle Dynamics and Maturation in Human iPSC-Derived Cardiomyocytes"
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Reduced PRDM16 expression significantly impairs the metabolic and
      structural maturation of hiPSC-CMs, leading to dysregulated sarcomeric
      protein expression ratios and compromised engineered heart tissue (EHT)
      function.
    explanation: >-
      The repository's own summary states what the deposited experiment shows:
      lowering PRDM16 in human cardiomyocytes impairs maturation and
      contractile tissue function, which is the human-cell counterpart of the
      proliferation and maturation arm of the mechanism curated above.
  notes: >-
    siRNA knockdown and lentiviral overexpression of PRDM16 in hiPSC-derived
    cardiomyocytes, directly probing the proliferation-maturation axis
    implicated in the PRDM16 loss-of-function mechanism curated above
    (reduced PRDM16 impairs metabolic/structural maturation and sarcomeric
    protein ratios; no linked PMID at time of curation).

experimental_models:
- name: PRDM16-Q187X proband-derived hiPSC-cardiomyocytes
  experimental_model_type: IPSC_DERIVED_MODEL
  cell_source: patient-derived iPSC
  culture_system: monolayer hiPSC-cardiomyocyte culture
  organism:
    preferred_term: human
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  cell_types:
  - preferred_term: cardiac muscle cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  publication: PMID:38113297
  description: >-
    Cardiomyocytes differentiated from induced pluripotent stem cells of the
    proband carrying the PRDM16 Q187X nonsense variant. This is the only human
    system in this entry that carries an actual LVNC8 genotype, which is what
    makes it the strongest available test of whether the proliferative arm of
    the mechanism operates in human cells rather than only in mouse and
    zebrafish. It was phenotyped alongside the Q187X knock-in mouse in the
    same study.
  evidence:
  - reference: PMID:38113297
    reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Induced pluripotent stem cell-derived cardiomyocytes were generated
      from a proband hosting a Q187X nonsense variant as an in vitro model
      and underwent proliferative and transcriptional analyses.
    explanation: >-
      Establishes the system's provenance from a genotyped LVNC8 proband and
      the analyses it underwent.
  modeled_mechanisms:
  - target: Impaired Cardiomyocyte Proliferation
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: CELLULAR
    description: >-
      Cardiomyocytes carrying the patient's own variant show a significant
      proliferative deficit with increased apoptosis, in human cells.
    limitations: >-
      hiPSC-cardiomyocytes are fetal-like and proliferation-competent, unlike
      adult human cardiomyocytes, so the deficit is measured against a
      developmental baseline that has no adult counterpart. The system is
      also derived from a single proband, so genetic background is not
      controlled.
    readouts:
    - name: Cardiomyocyte proliferation and apoptosis
      target: Impaired Cardiomyocyte Proliferation
      description: >-
        Proliferative and apoptotic indices in Q187X proband hiPSC-CMs versus
        control.
      direction: DECREASED
      interpretation: >-
        Reduced proliferation with increased apoptosis is the cellular deficit
        this node names, measured here in human cells.
      evidence:
      - reference: PMID:38113297
        reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
        supports: SUPPORT
        evidence_source: IN_VITRO
        snippet: >-
          Induced pluripotent stem cell-derived cardiomyocytes prepared from
          the PRDM16-Q187X proband demonstrated a statistically significant
          impairment in myocyte proliferation and increased apoptosis
          associated with transcriptional dysregulation of genes implicated
          in cardiac maturation, including TGF-β-associated transcripts.
        explanation: >-
          Reports both measurements and their direction in the
          genotype-matched human system.
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Using human induced pluripotent stem cell-derived cardiomyocytes
        (hiPSC-CMs) from Proband 1 and Prdm16-Q187X knock in mouse model, we
        demonstrate that PRDM16 regulates proliferation of cardiomyocytes in
        humans and mice.
      explanation: >-
        Attests that this system is informative for the proliferation node
        specifically, and that the human and mouse arms agree on it, which is
        what the node's cross-species claim rests on.

- name: H9c2 rat cardiomyoblast PRDM16 promoter-binding system
  experimental_model_type: CELL_LINE
  cell_source: immortalized rat cardiomyoblast line
  culture_system: monolayer cell culture with adenoviral expression
  organism:
    preferred_term: Norway rat
    term:
      id: NCBITaxon:10116
      label: Rattus norvegicus
  publication: PMID:38113297
  description: >-
    The immortalized rat cardiomyoblast line used for the loss- and
    gain-of-function and ChIP-PCR work that establishes PRDM16 binding at the
    TGFB3 promoter. It is a mechanistic reduction rather than a disease model:
    it carries no LVNC8 genotype and models no clinical phenotype, but it is
    where the repression step underlying the TGF-beta node was demonstrated.
  evidence:
  - reference: PMID:38113297
    reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      we used Prdm16 loss-and-gain-of-function studies in rat cardiac H9c2
      cardiomyoblasts
    explanation: >-
      Establishes the system and the bidirectional perturbation design behind
      the promoter-level claim.
  modeled_mechanisms:
  - target: TGF-beta Signaling Dysregulation
    relationship: PERTURBS
    fidelity: LOW
    model_scale: MOLECULAR
    description: >-
      PRDM16 was raised and lowered in this line and its binding at the TGFB3
      promoter assayed directly, establishing the repression step this node
      asserts.
    limitations: >-
      A rat immortalized cardiomyoblast line is neither human nor a
      cardiomyocyte, carries no LVNC8 variant, and expresses PRDM16 from an
      adenoviral construct rather than at endogenous dose. It establishes that
      PRDM16 can repress TGFB3, not that this repression sets the direction of
      TGF-beta signaling in patient myocardium; the conflicting in vivo
      directions recorded elsewhere in this entry are exactly why that
      distinction matters.
    readouts:
    - name: PRDM16 occupancy at the Tgfb3 promoter
      target: TGF-beta Signaling Dysregulation
      description: >-
        ChIP-PCR of Myc-tagged PRDM16 with histone H3K4 methylation state at
        the same region.
      direction: INCREASED
      interpretation: >-
        Direct promoter occupancy, with the H3K4me1 up and H3K4me3 down shift
        that accompanies repression, is the molecular basis of this node.
      evidence:
      - reference: PMID:38113297
        reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
        supports: SUPPORT
        evidence_source: IN_VITRO
        snippet: >-
          Using these primers, we performed ChIP-PCR of Myc-tagged PRDM16
          expressed via adenovirus in H9c2 cells and confirmed binding at the
          Tgfb3 and Tgfb2 promoter
        explanation: >-
          Reports the occupancy measurement this readout records, at Tgfb3 and
          also Tgfb2.
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Mechanistic studies were undertaken in H9c2 cardiomyoblasts to show
        that PRDM16 binds TGFB3 promoter and represses its transcription.
      explanation: >-
        Attests that this system is informative for the TGF-beta node: it is
        where the promoter-level repression the node is built on was
        demonstrated.

animal_models:
- name: Prdm16 cardiomyocyte-specific knockout mouse (Prdm16cKO)
  species: Mouse
  genotype: >-
    Prdm16 conditional knockout, cardiomyocyte-restricted via Xmlc2-Cre and,
    independently, cTnT-Cre (both lines called Prdm16cKO in the paper)
  genes:
  - preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  publication: PMID:34915728
  description: >-
    Conditional deletion of Prdm16 restricted to cardiomyocytes. Unlike earlier
    conditional Prdm16 lines, this model reproduces the left-ventricle-selective
    vulnerability seen in patients: it develops LV-specific dilation and
    systolic dysfunction together with biventricular noncompaction. Paired RNA
    sequencing, ChIP sequencing, single-cell RNA sequencing and spatial
    transcriptomics in the same model identify the direct transcriptional
    targets of PRDM16 and show that compact-layer cardiomyocytes lose their
    normal transcriptomic identity. It is the reference in vivo model for the
    compact-myocardium transcriptional arm of the LVNC8 mechanism.
  evidence:
  - reference: PMID:34915728
    reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Prdm16 cardiomyocyte-specific knockout (Prdm16cKO) mice were generated
      and analyzed for cardiac phenotypes.
    explanation: >-
      Establishes the model's construction and that it was characterized for
      cardiac phenotypes, which is what makes it usable as an in vivo model of
      this disease.
  - reference: PMID:34915728
    reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      indicating that cardiac phenotypes we observed in Prdm16cKO mice were
      not Cre driver line dependent
    explanation: >-
      Names why this line is the reference model rather than one of several:
      the phenotype was reproduced across two independent Cre drivers, which
      is the control the earlier conditional lines lacked and which matters
      because Cre driver is a known source of divergence between Prdm16
      knockout studies.
  modeled_mechanisms:
  - target: Loss of Compact Myocardium Transcriptional Identity
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: CELLULAR
    description: >-
      Single-cell and spatial transcriptomics in this model define the
      compact-to-trabecular identity shift that the node asserts, and ChIP
      sequencing identifies the direct PRDM16 targets responsible.
    limitations: >-
      Cardiomyocyte-restricted deletion removes Prdm16 from every cardiomyocyte,
      whereas human LVNC8 is a germline heterozygous state with residual PRDM16
      dose in all lineages, so the transcriptional shift is expected to be more
      complete here than in patients.
    evidence:
    - reference: PMID:34915728
      reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        PRDM16 functioned mechanistically as a compact myocardium-enriched
        transcription factor that activated compact myocardial genes while
        repressing trabecular myocardial genes in LV compact myocardium.
      explanation: >-
        Attests that this model is informative for the node: the dual
        activator/repressor role defining compact-myocardial identity was
        established in this knockout, which is what licenses reading the
        node off this model.
    readouts:
    - name: Compact-myocardial versus trabecular transcriptional signature
      target: Loss of Compact Myocardium Transcriptional Identity
      description: >-
        Single-cell RNA sequencing with spatial transcriptomics of LV compact
        myocardium, scored for compact- versus trabecular-identity genes.
      direction: ALTERED
      interpretation: >-
        A compact-layer cardiomyocyte reading out as trabecular is the direct
        measurement behind this node.
      evidence:
      - reference: PMID:34915728
        reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Consequently, Prdm16cKO LV compact myocardial cardiomyocytes shifted
          from their normal transcriptomic identity to a transcriptional
          signature resembling trabecular myocardial cardiomyocytes or
          neurons.
        explanation: >-
          Reports the transcriptomic measurement and its direction in this
          model.
  - target: Failed Ventricular Compaction
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: TISSUE
    description: >-
      The model develops biventricular noncompaction, the structural lesion
      this node names.
    limitations: >-
      Noncompaction here is biventricular, whereas the human disease label and
      the patient phenotype foreground the left ventricle; the chamber
      distribution is therefore broader in the model than in patients.
    evidence:
    - reference: PMID:34915728
      reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific
        dilation and dysfunction, as well as biventricular noncompaction,
        which fully recapitulated LVNC in patients.
      explanation: >-
        States that the model reproduces the noncompaction phenotype of
        patients, which is the claim this link makes.
  - target: Left Ventricular Dilation and Systolic Dysfunction
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: ORGANISM
    description: >-
      The model reproduces the left-ventricle-selective dilation and systolic
      dysfunction that distinguishes this disease from a generic
      cardiomyopathy, and was generated specifically because earlier
      conditional lines did not.
    limitations: >-
      Chamber selectivity is reproduced, and the paper offers the LV-restricted
      transcriptional program as its explanation, but presents that as an
      explanation for a subset of LVNC cardiomyopathies rather than a general
      one. How far it extends to PRDM16 patients specifically is untested.
    evidence:
    - reference: PMID:34915728
      reference_title: "PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific
        dilation and dysfunction, as well as biventricular noncompaction,
        which fully recapitulated LVNC in patients.
      explanation: >-
        Directly reports LV-specific dilation and dysfunction in the model and
        its correspondence to the patient phenotype.

- name: Prdm16Q187X knock-in mouse
  species: Mouse
  genotype: Prdm16Q187X knock-in (heterozygous Prdm16Q187X/WT and homozygous Prdm16Q187X/Q187X)
  genes:
  - preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  publication: PMID:38113297
  description: >-
    CRISPR-mediated knock-in of the patient-derived Q187X nonsense allele,
    generated alongside iPSC-cardiomyocytes from the proband carrying the same
    variant. It is the only mouse in this entry built on a specific human
    LVNC8 allele rather than on gene deletion (the zebrafish model also
    expresses a human truncation allele), which makes it the strongest
    available mammalian test of allele-level causality. Homozygotes are embryonically
    lethal with an underdeveloped compact myocardium; heterozygotes show
    fibrosis and age-dependent loss of TGF-beta expression, but smaller rather
    than dilated ventricles.
  evidence:
  - reference: PMID:38113297
    reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      CRISPR (clustered regularly interspaced short palindromic
      repeats)-mediated knock-in mouse model hosting the Prdm16Q187X allele
      was generated and subjected to ECG, histological, and transcriptional
      analysis.
    explanation: >-
      Establishes that the model carries the patient's own nonsense allele and
      the phenotyping it underwent.
  modeled_mechanisms:
  - target: Failed Ventricular Compaction
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: TISSUE
    description: >-
      Homozygous Q187X animals fail to develop a normal compact myocardium,
      tying the human nonsense allele directly to the compaction defect.
    limitations: >-
      The compaction phenotype requires the homozygous state, which is
      embryonically lethal and has no human counterpart: LVNC8 patients are
      heterozygous. The allele's compaction effect in mice is therefore
      demonstrated at a dose humans never carry.
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Homozygous Prdm16Q187X/Q187X mice demonstrated an underdeveloped
        compact myocardium and were embryonically lethal.
      explanation: >-
        Reports the compaction defect and the zygosity at which it appears.
  - target: TGF-beta Signaling Dysregulation
    relationship: FAILS_TO_RECAPITULATE
    fidelity: LOW
    model_scale: MOLECULAR
    description: >-
      Heterozygotes do show TGF-beta dysregulation, but in the opposite
      direction from this node: TGF-beta expression falls with age, where
      losing a repressor of TGFB3 predicts, and the node asserts, an increase.
    limitations: >-
      This is a direction mismatch on the node's asserted quantity rather than
      a missing measurement, which is why the link is FAILS_TO_RECAPITULATE
      and not PARTIALLY_RECAPITULATES: the model moves the opposite way. It
      also conflicts with the cardiac-specific Prdm16 null model below, where
      TGF-beta signaling is activated, and with the patient-derived
      iPSC-cardiomyocytes, whose proliferative deficit is attributed to
      TGF-beta activation. Allele class, dose, Cre driver and age at
      measurement all differ across these systems. This paper's own proposal
      is that PRDM16 regulates TGF-beta bidirectionally in a
      temporally-dependent manner, which would reconcile them; until that is
      tested across models this link must not be used to infer the direction
      of the TGF-beta change in patients at any given stage. See discussion
      gap_lvnc8_tgfbeta_direction_conflict.
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller
        ventricular dimensions, heightened fibrosis, and age-dependent loss
        of TGF-β expression.
      explanation: >-
        Substantiates the FAILS_TO_RECAPITULATE claim: the model does measure
        TGF-beta in the genotype-matched heterozygote, and the measurement
        falls with age where this node asserts an increase.
    readouts:
    - name: Myocardial TGF-beta expression
      target: TGF-beta Signaling Dysregulation
      description: >-
        Transcriptional analysis of Prdm16Q187X/WT hearts across age.
      direction: DECREASED
      interpretation: >-
        An age-dependent fall in TGF-beta expression is the measured
        dysregulation in this model.
      evidence:
      - reference: PMID:38113297
        reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller
          ventricular dimensions, heightened fibrosis, and age-dependent loss
          of TGF-β expression.
        explanation: >-
          Reports the direction and age dependence of the TGF-beta measurement.
  - target: Myocardial Fibrosis
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: TISSUE
    description: >-
      The genotype-matched heterozygote develops heightened myocardial
      fibrosis, the one component of the human phenotype this model
      reproduces cleanly.
    limitations: >-
      Fibrosis is reported qualitatively as heightened, without a quantitative
      collagen measure, and no human myocardial fibrosis data exist for
      PRDM16 carriers to compare against.
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller
        ventricular dimensions, heightened fibrosis, and age-dependent loss
        of TGF-β expression.
      explanation: >-
        Reports heightened fibrosis in the genotype-matched heterozygote,
        substantiating the claim made in this model's other links that the
        fibrotic component is the part it reproduces.
  - target: Left Ventricular Dilation and Systolic Dysfunction
    relationship: FAILS_TO_RECAPITULATE
    fidelity: LOW
    model_scale: ORGANISM
    description: >-
      The heterozygous state matching the human genotype produces smaller
      ventricular dimensions, the opposite of the ventricular dilation seen in
      patients carrying this class of variant.
    limitations: >-
      This is a substantive negative result, not a gap in phenotyping: the
      heterozygous Q187X mouse is the genotype-matched animal and it diverges
      in direction from the human phenotype on this node. Ventricular
      dimensions from this model must not be used to infer human chamber
      remodeling, and any therapeutic inference about reverse remodeling drawn
      from it would be inverted. Fibrosis is reproduced, so the model remains
      informative for the fibrotic component while failing on chamber size.
    readouts:
    - name: Ventricular chamber dimensions
      target: Left Ventricular Dilation and Systolic Dysfunction
      description: >-
        Echocardiographic and histological ventricular dimensions in
        Prdm16Q187X/WT mice versus wild-type littermates.
      direction: DECREASED
      interpretation: >-
        Decreased chamber dimension in the model against dilation in patients
        is the direction mismatch that makes this a failure to recapitulate.
      evidence:
      - reference: PMID:38113297
        reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller
          ventricular dimensions, heightened fibrosis, and age-dependent loss
          of TGF-β expression.
        explanation: >-
          Reports smaller, not larger, ventricular dimensions in the
          genotype-matched heterozygote.
    evidence:
    - reference: PMID:38113297
      reference_title: "Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller
        ventricular dimensions, heightened fibrosis, and age-dependent loss
        of TGF-β expression.
      explanation: >-
        Supports the FAILS_TO_RECAPITULATE claim this link makes: the
        genotype-matched heterozygote moves in the opposite direction on
        chamber size from the human phenotype this node describes, which is
        the failure being asserted rather than a contradiction of it.

- name: Prdm16csp1/wt systemic monoallelic mouse
  species: Mouse
  genotype: Prdm16csp1/wt (systemic, monoallelic Prdm16 inactivation)
  genes:
  - preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  publication: PMID:37842925
  description: >-
    Systemic heterozygous Prdm16 inactivation, the closest genotype match in
    this entry to the human heterozygous state. Profiled by transcriptomics,
    proteomics and metabolomics in both sexes to capture the earliest
    pathological window rather than end-stage disease. It is the source of the
    metabolic arm of the LVNC8 mechanism and of the sex-dimorphism observation:
    female animals are more severely affected.
  evidence:
  - reference: PMID:37842925
    reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      This study performed in-depth pathophysiological and molecular analyses
      of male and female Prdm16csp1/wt mice that carry systemic, monoallelic
      Prdm16 gene inactivation.
    explanation: >-
      Establishes the model's genotype as monoallelic and systemic, which is
      what makes it the closest available match to the human heterozygous
      state.
  modeled_mechanisms:
  - target: Cardiac Metabolic Dysregulation
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: MOLECULAR
    description: >-
      Metabolomic profiling of cardiac tissue defines the substrate-utilization
      and oxidative-stress changes this node asserts, at the earliest
      detectable stage.
    limitations: >-
      The metabolic phenotype is sex-dimorphic in this model and no equivalent
      human cardiac metabolomic data exist for PRDM16 carriers, so neither the
      magnitude nor the sex dependence has been confirmed in patients.
    evidence:
    - reference: PMID:37842925
      reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Metabolic alterations and transcriptional dysregulation in
        Prdm16csp1/wt affect cardiac tissue.
      explanation: >-
        Attests that this model is informative for the cardiac metabolic
        node specifically, locating the metabolic alterations in cardiac
        tissue rather than in the adipose biology PRDM16 is better known
        for.
    readouts:
    - name: Cardiac glutathione and inosine monophosphate
      target: Cardiac Metabolic Dysregulation
      description: >-
        Targeted metabolomics of Prdm16csp1/wt cardiac tissue.
      direction: ALTERED
      interpretation: >-
        Falling glutathione with rising inosine monophosphate is read by the
        authors as oxidative stress plus dysregulated energetics, which is the
        content of this node.
      evidence:
      - reference: PMID:37842925
        reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Prdm16csp1/wt cardiac tissue revealed diminished glutathione (GSH)
          and increased inosine monophosphate (IMP) levels indicating
          oxidative stress and a dysregulated energetics, respectively.
        explanation: >-
          Reports both measurements and the directions this readout records.
    - name: Cardiac intermediary metabolite pools
      target: Cardiac Metabolic Dysregulation
      description: >-
        Untargeted metabolomics across amino acid, glycerol, glycolytic and
        tricarboxylic acid cycle pathways in both sexes.
      direction: DECREASED
      interpretation: >-
        Broad reduction across central carbon and amino acid metabolism is the
        substrate-utilization deficit underlying this node.
      evidence:
      - reference: PMID:37842925
        reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Prdm16csp1/wt cardiac tissue of both sexes showed reductions in
          metabolites associated with amino acid as well as glycerol
          metabolism, glycolysis, and the tricarboxylic acid cycle.
        explanation: >-
          Reports the measured direction across the metabolite classes named
          in this readout.
  - target: Left Ventricular Dilation and Systolic Dysfunction
    relationship: PARTIALLY_RECAPITULATES
    fidelity: LOW
    model_scale: ORGANISM
    description: >-
      Systolic performance is reduced, matching the human phenotype, but the
      hearts are hypoplastic rather than dilated.
    limitations: >-
      Only the systolic-dysfunction half of this node is reproduced. Chamber
      geometry moves the wrong way: hypoplastic hearts are not dilated hearts,
      the same divergence the Q187X heterozygote shows. Both monoallelic mouse
      models therefore fail on the dilation component, which is worth weighing
      before treating either as a model of the remodeling process.
    evidence:
    - reference: PMID:37842925
      reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Monoallelic, global Prdm16 mutation diminishes cardiac performance
        in Prdm16csp1/wt mice.
      explanation: >-
        Attests that the monoallelic model does report on cardiac
        performance, which is the half of this node it partially
        recapitulates.
    readouts:
    - name: Systolic performance
      target: Left Ventricular Dilation and Systolic Dysfunction
      description: >-
        Echocardiographic systolic function in male and female Prdm16csp1/wt
        mice up to 8 months.
      direction: DECREASED
      interpretation: >-
        Diminished systolic performance is the component of this node the
        model does reproduce; the sex difference is a property of the model
        with no confirmed human counterpart.
      evidence:
      - reference: PMID:37842925
        reference_title: "Prdm16 mutation determines sex-specific cardiac metabolism and identifies two novel cardiac metabolic regulators."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Prdm16csp1/wt mice are viable up to 8 months, develop hypoplastic
          hearts, and diminished systolic performance that is more pronounced
          in female mice.
        explanation: >-
          Reports both the systolic deficit this readout measures and the
          hypoplastic chamber geometry that limits the link.

- name: Prdm16 cardiomyocyte-specific deletion mouse (conduction-system phenotype)
  species: Mouse
  genotype: >-
    Prdm16lox/lox;Sm22alpha-Cre (called Prdm16cKO in the paper), deleting
    Prdm16 exon 9 in cardiomyocytes from early cardiac development onward
  genes:
  - preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  publication: PMID:39304345
  description: >-
    An independently generated cardiomyocyte-specific Prdm16 deletion, analysed
    by combined single-cell RNA and ATAC sequencing. It is kept separate from
    the Prdm16cKO model above because it interrogates a different arm of the
    mechanism: rather than the compact-versus-trabecular axis, it establishes
    that PRDM16 suppresses conduction-system and atrial fates, and that its
    loss expands the distal ventricular conduction system. This is the only
    in vivo source for the conduction and arrhythmia arm of this entry.
  evidence:
  - reference: PMID:39304345
    reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      By combined RNA+ATAC single-cell sequencing, we found that PRDM16
      favors ventricular working cardiomyocyte identity, by opposing the
      activity of master regulators of ventricular conduction and atrial
      fate.
    explanation: >-
      Establishes what this model was used to determine and the single-cell
      method that grounds the cell-fate claim.
  - reference: PMID:39304345
    reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Although our Sm22α-Cre driver also eliminated PRDM16 expression in SMCs
    explanation: >-
      The authors' own statement of the driver's off-target, recorded here
      because the model's genotype would otherwise be read as restricted to
      cardiomyocytes. They go on to argue the cardiomyocyte loss is the
      primary culprit, but the smooth-muscle deletion is real and is why this
      link carries that caveat.
  modeled_mechanisms:
  - target: Ventricular Conduction System Hyperplasia and Atrial-Fate Derepression
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: TISSUE
    description: >-
      Developmental myocardial Prdm16 loss expands the distal ventricular
      conduction system, the structural change this node asserts.
    limitations: >-
      The Sm22alpha-Cre driver is not cardiomyocyte-exclusive: the authors
      report that it also eliminates PRDM16 in smooth muscle cells, and argue
      the cardiomyocyte loss is the primary culprit on the grounds that smooth
      muscle coverage was unaffected. Deletion is also developmental, where
      patients carry partial lifelong haploinsufficiency; whether that
      produces conduction-system expansion of comparable extent has not been
      shown, and no human histological counterpart is available.
    evidence:
    - reference: PMID:39304345
      reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Hence, PRDM16 plays an indispensable role during cardiac development
        by driving ventricular working cardiomyocyte identity.
      explanation: >-
        Attests the model's standing for this node: the conduction-system
        finding is the paper's basis for concluding that PRDM16 drives
        ventricular working cardiomyocyte identity against alternative
        fates.
    readouts:
    - name: Distal ventricular conduction system extent
      target: Ventricular Conduction System Hyperplasia and Atrial-Fate Derepression
      description: >-
        Histological and single-cell assessment of conduction-system tissue
        within the ventricular myocardium.
      direction: INCREASED
      interpretation: >-
        Hyperplasia of the distal conduction system is the direct measurement
        behind this node.
      evidence:
      - reference: PMID:39304345
        reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Myocardial loss of PRDM16 during development resulted in hyperplasia
          of the (distal) ventricular conduction system.
        explanation: >-
          Reports the measurement and its direction in this model.
  - target: Arrhythmia and Ventricular Pre-excitation
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    description: >-
      The model develops abnormal postnatal electrophysiology and premature
      death, giving an in vivo arrhythmic phenotype downstream of the
      conduction-system expansion.
    limitations: >-
      The model reports abnormal electrophysiology and premature death, not
      ventricular pre-excitation specifically. The accessory-pathway phenotype
      that names this node is documented in a human PRDM16 carrier and has no
      demonstrated counterpart in this mouse, so the model supports the
      arrhythmia half of the node and not the pre-excitation half.
    evidence:
    - reference: PMID:39304345
      reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        The observed prolonged QRS is indeed compatible with defects in the
        distal VCS
      explanation: >-
        The authors' own reading of their result, tying the measured
        conduction abnormality back to the distal conduction-system defect
        this model produces. That is precisely what makes the model
        informative for an arrhythmia node fed by conduction-system
        hyperplasia, rather than merely coincident with one.
    readouts:
    - name: Postnatal cardiac electrophysiology
      target: Arrhythmia and Ventricular Pre-excitation
      description: >-
        Electrophysiological assessment of postnatal hearts after
        cardiomyocyte-specific Prdm16 deletion.
      direction: ALTERED
      interpretation: >-
        Abnormal postnatal electrophysiology culminating in premature death is
        the arrhythmic outcome this model reports.
      evidence:
      - reference: PMID:39304345
        reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          cardiomyocyte-specific deletion of Prdm16 during cardiac development
          results in contractile dysfunction and abnormal electrophysiology of
          the postnatal heart, resulting in premature death
        explanation: >-
          Reports the electrophysiological abnormality and its lethal outcome
          in this model.
      - reference: PMID:39304345
        reference_title: "PRDM16 determines specification of ventricular cardiomyocytes by suppressing alternative cell fates."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          already at P7, Prdm16cKO pups showed an aberrant electrocardiogram
          (ECG), that is, a prolonged QRS duration
        explanation: >-
          Names the specific electrocardiographic abnormality and the age at
          which it appears, which the summary sentence above leaves
          unquantified.

- name: Zebrafish prdm16 haploinsufficiency and truncation model
  species: Zebrafish
  genotype: prdm16 knockdown (haploinsufficiency) and human PRDM16 truncation mutant expression
  genes:
  - preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  publication: PMID:23768516
  description: >-
    The original functional model accompanying the discovery that PRDM16
    mutation causes the cardiomyopathy of 1p36 deletion syndrome and a share of
    nonsyndromic LVNC and DCM. Both reduced prdm16 dose and a human truncation
    allele were modeled, producing contractile dysfunction, partial
    cardiomyocyte uncoupling, and impaired cardiomyocyte proliferative
    capacity. It is the earliest evidence tying the proliferative arm of this
    mechanism to the human genotype.
  evidence:
  - reference: PMID:23768516
    reference_title: "Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Modeling of PRDM16 haploinsufficiency and a human truncation mutant in
      zebrafish resulted in both contractile dysfunction and partial
      uncoupling of cardiomyocytes and also revealed evidence of impaired
      cardiomyocyte proliferative capacity.
    explanation: >-
      Establishes that both the dose-reduction and human-allele arms of the
      model were built and what cardiac phenotypes they produced.
  modeled_mechanisms:
  - target: Impaired Cardiomyocyte Proliferation
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: CELLULAR
    description: >-
      Reduced prdm16 dose and a human truncation allele both impair
      cardiomyocyte proliferative capacity, the claim this node makes.
    limitations: >-
      Zebrafish cardiomyocytes retain proliferative and regenerative capacity
      that mammalian cardiomyocytes lose after birth, so the baseline biology
      of the readout differs from the human one. The zebrafish heart is also
      two-chambered and has no compact-versus-trabecular left ventricular
      architecture, so this model cannot address the chamber-specific arm of
      the mechanism at all.
    evidence:
    - reference: PMID:23768516
      reference_title: "Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Modeling of PRDM16 haploinsufficiency and a human truncation mutant in
        zebrafish resulted in both contractile dysfunction and partial
        uncoupling of cardiomyocytes and also revealed evidence of impaired
        cardiomyocyte proliferative capacity.
      explanation: >-
        Reports the proliferative deficit in both arms of the model.
  - target: Left Ventricular Dilation and Systolic Dysfunction
    relationship: PARTIALLY_RECAPITULATES
    fidelity: LOW
    model_scale: ORGANISM
    description: >-
      Contractile dysfunction is reproduced; ventricular dilation is not
      assessable in this organism.
    limitations: >-
      The zebrafish heart has a single ventricle with no left-ventricular
      counterpart, so the chamber-specific dilation this node names cannot be
      observed here. Only the contractile-dysfunction component transfers, and
      the partial cardiomyocyte uncoupling reported alongside it has no
      established human correlate in LVNC8.
    evidence:
    - reference: PMID:23768516
      reference_title: "Fine mapping of the 1p36 deletion syndrome identifies mutation of PRDM16 as a cause of cardiomyopathy."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Modeling of PRDM16 haploinsufficiency and a human truncation mutant in
        zebrafish resulted in both contractile dysfunction and partial
        uncoupling of cardiomyocytes and also revealed evidence of impaired
        cardiomyocyte proliferative capacity.
      explanation: >-
        Reports the contractile dysfunction that is the transferable half of
        this link.

- name: Cardiac-specific Prdm16 conditional knockout mouse (conduction and fibrosis phenotype)
  species: Mouse
  genotype: >-
    Cardiac-specific Prdm16 conditional knockout via alpha-MHC (Myh6)-Cre
    (Prdm16-null hearts); the driver is not named in this paper's own
    abstract-only record here and is attributed by PMID:37395136, which
    identifies its model as similar to Nam et al's Myh6-Cre knockout
  genes:
  - preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  publication: PMID:32083975
  description: >-
    Cardiac-restricted Prdm16 null model phenotyped by electrocardiography,
    fibrosis histology and left ventricular RNA sequencing. It is the only
    model in this entry that measures TGF-beta pathway activity in vivo and
    then tests it pharmacologically: TGF-beta signaling is activated in
    Prdm16-null hearts, but blocking the TGF-beta receptor does not rescue the
    conduction defect. That negative rescue result separates the fibrotic and
    conduction arms of the mechanism, and the accompanying ion-channel
    transcript dysregulation offers a TGF-beta-independent route to the
    arrhythmia node.
  evidence:
  - reference: PMID:32083975
    reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      We used cardiac-specific Prdm16 conditional knockout mice to examine
      cardiac function by electrocardiography.
    explanation: >-
      Establishes the model and the electrophysiological phenotyping that makes
      it usable for the conduction and arrhythmia arm of this entry.
  modeled_mechanisms:
  - target: TGF-beta Signaling Dysregulation
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: MOLECULAR
    description: >-
      TGF-beta signaling is activated in Prdm16-null hearts at both ligand
      transcript and downstream effector level, the direction predicted by
      PRDM16 acting as a repressor of TGFB transcription.
    limitations: >-
      This model's direction conflicts with the Prdm16Q187X heterozygote, which
      shows age-dependent loss of TGF-beta expression. The two differ in
      allele class (complete cardiac null versus a heterozygous nonsense
      variant), dose and timepoint. The Q187X paper proposes that PRDM16
      regulates TGF-beta bidirectionally in a temporally-dependent manner,
      which would make the two findings phases of one mechanism; that has not
      been tested across models, so the sign of the TGF-beta change in human
      LVNC8 should not be inferred from either model alone. The driver is alpha-MHC (Myh6)-Cre, attributed by
      PMID:37395136 rather than stated in this paper's own record here, and
      it matters: Myh6-Cre knockouts are reported to give hypertrophy in one
      model and LV dilation in another, and a later paper judged the earlier
      conditional Prdm16 lines not to mirror the patient LVNC phenotype.
    readouts:
    - name: Myocardial TGF-beta ligand transcripts and Smad2 phosphorylation
      target: TGF-beta Signaling Dysregulation
      description: >-
        Quantitative real-time PCR for Tgfb1-3 and immunoblot for
        phosphorylated Smad2 in Prdm16-null hearts.
      direction: INCREASED
      interpretation: >-
        Raised ligand transcripts together with increased phospho-Smad2 is
        pathway activation measured at two levels rather than a transcript
        change alone.
      evidence:
      - reference: PMID:32083975
        reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Moreover, TGF-β signaling was activated in Prdm16-null hearts, as
          evidenced by increased Tgfb1-3 transcript levels and phosphorylated
          Smad2.
        explanation: >-
          Reports both measurements and the activation direction this readout
          records.
    evidence:
    - reference: PMID:32083975
      reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Moreover, TGF-β signaling was activated in Prdm16-null hearts, as
        evidenced by increased Tgfb1-3 transcript levels and phosphorylated
        Smad2.
      explanation: >-
        Attests that this model is informative for the TGF-beta node: it is the
        in vivo demonstration that removing PRDM16 de-represses TGF-beta
        signaling, which is what the promoter-binding work predicts.
  - target: Myocardial Fibrosis
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: TISSUE
    description: >-
      Prdm16-null hearts develop increased fibrosis with cardiomyocyte
      hypertrophy, quantified by trichrome staining, densitometry and
      hydroxyproline assay and accompanied by upregulated extracellular-matrix
      and myofibroblast transcripts.
    limitations: >-
      Fibrosis here is measured in a complete cardiac null; patients are
      heterozygous, and no quantitative human myocardial fibrosis data exist
      for PRDM16 carriers to calibrate the magnitude against.
    readouts:
    - name: Myocardial collagen content
      target: Myocardial Fibrosis
      description: >-
        Trichrome staining with densitometry and hydroxyproline assay in
        Prdm16-null hearts versus wild-type.
      direction: INCREASED
      interpretation: >-
        Three independent measures of collagen burden agreeing in direction is
        what makes this more than a histological impression.
      evidence:
      - reference: PMID:32083975
        reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Prdm16-null hearts showed greater fibrosis and cardiomyocyte
          hypertrophy.
        explanation: >-
          Reports the fibrosis measurement and its direction in this model.
    evidence:
    - reference: PMID:32083975
      reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Prdm16-null hearts showed greater fibrosis and cardiomyocyte
        hypertrophy.
      explanation: >-
        Attests that this model is informative for the fibrosis phenotype,
        which the entry curates but which no model was previously linked to.
  - target: Arrhythmia and Ventricular Pre-excitation
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    description: >-
      Prdm16-null hearts show measurable conduction and repolarization
      abnormalities (prolonged QRS and QTc) alongside dysregulated ion channel
      transcripts, giving a TGF-beta-independent substrate for the arrhythmia
      node.
    limitations: >-
      The phenotype is conduction slowing and repolarization prolongation, not
      the accessory-pathway pre-excitation that names this node; no
      pre-excitation is reported in this model. Blocking the TGF-beta receptor
      does not reverse the conduction abnormality, so the arrhythmic substrate
      here is not downstream of the TGF-beta arm and should not be treated as
      such.
    readouts:
    - name: QRS duration and QTc interval
      target: Arrhythmia and Ventricular Pre-excitation
      description: >-
        Surface electrocardiography in cardiac-specific Prdm16 knockout mice
        versus wild-type.
      direction: INCREASED
      interpretation: >-
        Prolonged QRS and QTc are the quantitative conduction and
        repolarization abnormalities behind this node in this model.
      evidence:
      - reference: PMID:32083975
        reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          QRS duration and QTc interval increased significantly in
          cardiac-specific Prdm16 knockout animals compared with wild-type
          mice.
        explanation: >-
          Reports both electrocardiographic measurements and their direction.
    - name: Ventricular ion channel transcript expression
      target: Arrhythmia and Ventricular Pre-excitation
      description: >-
        RNA sequencing of left ventricular tissue, assessed for ion channel
        gene expression.
      direction: ALTERED
      interpretation: >-
        Dysregulation of Kcne1, Scn5a, Cacna1h and Cacna2d2 is the proposed
        molecular basis of the conduction phenotype and is independent of the
        TGF-beta arm.
      evidence:
      - reference: PMID:32083975
        reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          Prdm16-null hearts experienced dysregulated expression of ion channel
          genes, including Kcne1, Scn5a, Cacna1h, and Cacna2d2.
        explanation: >-
          Names the dysregulated channel genes this readout measures.
    evidence:
    - reference: PMID:32083975
      reference_title: "Cardiac-specific inactivation of Prdm16 effects cardiac conduction abnormalities and cardiomyopathy-associated phenotypes."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        However, the inhibition of TGF-β receptor did not reverse the
        aberrations in conduction in cardiac-specific Prdm16 knockout mice.
      explanation: >-
        A pharmacological rescue that failed, which is what makes this model
        informative for the arrhythmia node specifically: it establishes the
        conduction phenotype as separable from the TGF-beta arm rather than
        downstream of it.

- name: Sex-stratified cardiac-specific Prdm16 conditional knockout mouse
  species: Mouse
  genotype: >-
    Cardiac-specific Prdm16 conditional knockout via alpha-MHC (Myh6)-Cre,
    analysed by sex
  genes:
  - preferred_term: PRDM16
    term:
      id: hgnc:14000
      label: PRDM16
  publication: PMID:37395136
  description: >-
    A cardiac-specific Prdm16 knockout generated as the animal arm of a
    multi-institutional 1p36 deletion cohort study and analysed by sex, with
    echocardiography at 4 and 6 to 7 months and fibrosis histology at 7 months.
    Its value is that the sex effect it reports is paired with human data in
    the same paper, making it the one place in this entry where a
    model-derived observation is tested against patients rather than only
    asserted.
  evidence:
  - reference: PMID:37395136
    reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      A cardiac-specific Prdm16 knockout mouse (Prdm16 conditional knockout)
      was generated.
    explanation: >-
      Establishes that the study built its own animal model alongside the
      patient cohort.
  modeled_mechanisms:
  - target: Myocardial Fibrosis
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: TISSUE
    description: >-
      Fibrosis develops with an incidence and severity that differ by sex,
      assessed by histology and qPCR at 7 months.
    limitations: >-
      The sex dependence of the fibrotic response has no confirmed human
      counterpart, and the model is a cardiac-restricted null against
      germline heterozygosity in patients.
    evidence:
    - reference: PMID:37395136
      reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        We find sex-specific differences in the incidence and the severity of
        contractile dysfunction and fibrosis in female Prdm16 conditional
        knockout mice.
      explanation: >-
        Reports fibrosis as one of the two sex-stratified outcomes measured,
        linking this model to the fibrosis phenotype the entry curates.
  - target: Left Ventricular Dilation and Systolic Dysfunction
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    description: >-
      Contractile dysfunction and fibrosis develop with an incidence and
      severity that differ by sex, more severe in females, and female animals
      carry significantly elevated mortality.
    limitations: >-
      The reported outcome is contractile dysfunction with fibrosis rather than
      chamber dilation specifically, so this link covers the systolic-failure
      half of the node. The model is a cardiac-restricted null, whereas LVNC8
      patients are germline heterozygotes, and the human comparison in the same
      paper is a contiguous-gene-deletion cohort rather than nonsyndromic
      PRDM16 variant carriers.
    readouts:
    - name: Sex-stratified contractile dysfunction and fibrosis
      target: Left Ventricular Dilation and Systolic Dysfunction
      description: >-
        Echocardiography at 4 and 6 to 7 months with fibrosis histology and
        qPCR at 7 months, analysed separately in male and female animals.
      direction: DECREASED
      interpretation: >-
        Reduced contractile function with greater fibrosis in females is the
        measured phenotype; the sex difference is the finding, not an
        incidental stratification.
      evidence:
      - reference: PMID:37395136
        reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          We find sex-specific differences in the incidence and the severity of
          contractile dysfunction and fibrosis in female Prdm16 conditional
          knockout mice.
        explanation: >-
          Reports the sex-stratified contractile and fibrotic measurements this
          readout records.
    evidence:
    - reference: PMID:37395136
      reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        female Prdm16 conditional knockout mice demonstrate significantly
        elevated risk of mortality (P=0.0003)
      explanation: >-
        Recorded on the link rather than as a readout because mortality is a
        downstream consequence, not a measure of chamber dilation or systolic
        function. It is kept because it sizes the severity of the sex effect
        this link records. Directness is INDIRECT: survival is attributed to
        the contractile phenotype by co-occurrence in the same animals rather
        than by a demonstrated mechanism.
    - reference: PMID:37395136
      reference_title: "PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        We find sex-specific differences in the incidence and the severity of
        contractile dysfunction and fibrosis in female Prdm16 conditional
        knockout mice.
      explanation: >-
        Attests that this model is informative for the systolic-dysfunction
        node and identifies sex as a modifier of it, a claim the same paper
        then tests in patients.

references:
- reference: PMID:20301486
  title: Dilated Cardiomyopathy Overview.
  tags:
  - GeneReviews

📚

References & Deep Research

References

1

PMID:20301486

Dilated Cardiomyopathy Overview.

No top-level findings curated for this source.

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (3)

Record notes

Related entries: kb/disorders/Left_Ventricular_Noncompaction.yaml (MONDO:0018901, the polygenic umbrella LVNC entry) and kb/disorders/Dilated_Cardiomyopathy.yaml / Dilated_Cardiomyopathy_1AA.yaml (ACTN2, which models an analogous noncompaction-or-dilation dual phenotype). PRDM16 is also the gene underlying the cardiomyopathy component of 1p36 deletion syndrome (PMID:23768516); that syndromic, contiguous-gene-deletion context is distinct from this nonsyndromic, single-gene entity and its mechanism is not modeled here. Data from 1p36 deletion cohorts are used where they isolate PRDM16's own contribution by comparing deletions that remove the gene against deletions that spare it (PMID:37395136, supporting the penetrance record in `prevalence` and the transplant-endpoint evidence); every such record states that its population is the deletion syndrome rather than nonsyndromic LVNC8, because other genes in the deletion interval may modify the risk. PRDM16 is independently well known as the master regulator of brown/beige adipocyte fate; that adipose biology is unrelated to the cardiac mechanism curated below and was excluded during literature triage (NEC risk noted on issue 8747). Sources fetched but deliberately not cited: DOI:10.1007/s12265-023-10459-6 (Walsh 2023) and DOI:10.1016/j.jacc.2014.08.030 (Arbustini 2014) resolved to empty ("content_type: unavailable") DOI-keyed caches, so both were re-fetched and cited under their PMID identifiers instead (PMID:38019448, PMID:25443708) once full text was confirmed available. At the time PMID citations were snippet-validated by tooling and DOI citations were not, because `DOI:` was then in `skip_prefixes`; PR 11931 removed it, so both are now checked. DOI:10.1038/ncb3411 (Kodo 2016) and DOI:10.1161/CIRCULATIONAHA.121.056666 (Wu 2022) are the same papers already cited here under PMID:27642787 and PMID:34915728 respectively, so no separate DOI-keyed citation was added. DOI:10.17169/refubium-41680 (Theisen 2024, an unpublished doctoral thesis) reports the same Prdm16csp1/wt mouse line and sex-specific metabolic phenotype as the peer-reviewed PMID:37842925 (Kuhnisch et al. 2023), which is cited instead. The ESC 2023 cardiomyopathy-guidelines commentary (DOI:10.1093/eurheartjsupp/suae002) is a generic classification-scheme overview with no LVNC8- or PRDM16-specific quotable claim beyond what PMID:25443708 already supports with concrete criteria, so it was left uncited rather than cited for its abstract alone. A second falcon deep-research round (2026-09-06) added PMID:32083975 (cardiac-specific Prdm16 null: TGF-beta activation, QRS/QTc prolongation, ion-channel dysregulation), PMID:37395136 (1p36 deletion cohort with a sex-stratified Prdm16 knockout), PMID:31959004 and PMID:39420976 (LVNC outcome and prevalence meta-analyses), and trials NCT06024759 and NCT03572569. Sources from that round deliberately not cited: DOI:10.20944/preprints202507.1652.v1 (Martinez-Tittonel 2025) is an unpublished Preprints.org preprint whose diagnostic-criteria content duplicates what PMID:25443708 already supports from a peer-reviewed source; NCT04265040 (TORCH-Plus) is a broad multi-cardiomyopathy cohort with no LVNC- or PRDM16-specific arm; and DOI:10.1101/2020.01.03.19015602 is the medRxiv preprint of PMID:33500567, cited here under its PMID. The remaining DOIs that round returned resolve to papers already cited under their PMIDs.

Augment: Left Ventricular Noncompaction 8 (edge evidence, animal models, prevalence, trials) · 2026-09-06T14:56:49Z · View source

Second-round augmentation of the existing LVNC8 (PRDM16) entry. Deep research: a fresh falcon (Edison) run on 2026-09-06 (684s, 36 citations; frontmatter reports 13/13 references verified, confabulation_rate 0.0, and 23/23 terms verified). Its needs_review flag is set only by a template-rendering artifact, the literal string 'if available' recorded as a reported label for MONDO:0014152; the CURIE itself is correct and no term was bound from that list without independent checking. The report cites by DOI rather than PMID, so DOIs were resolved through the PMC ID converter and cited under PMIDs, which are snippet-validated by the gating validator where DOI-keyed items are not. What was added: (1) evidence on all 14 pathophysiology downstream causal edges, which previously had none, each quoting a source that makes the causal claim rather than reusing a node citation, with directness INDIRECT where the source establishes co-occurrence rather than a demonstrated sequence; (2) a new animal_models section with 7 models and 15 modeled_mechanisms links carrying readouts, fidelity, model_scale and limitations, including one FAILS_TO_RECAPITULATE link recording that the genotype-matched heterozygous Prdm16Q187X mouse shows smaller rather than dilated ventricles; (3) a new prevalence section, adult LVNC point prevalence 0.5 percent and cumulative cardiomyopathy in PRDM16-deleted 1p36 individuals at 29.1 percent, both flagged as broader than LVNC8 itself; (4) a new clinical_trials section with two observational registries; (5) two new discussions, a HUMAN_MODEL_MISMATCH recording that Prdm16-null hearts show TGF-beta activation while the genotype-matched Q187X heterozygote shows age-dependent loss, and a KNOWLEDGE_GAP on the female-predominant severity signal seen in two mouse lines and in 1p36 deletion patients; (6) evidence added to the dataset record quoting its GEO summary, to the Cardiac Transplantation treatment, and to the three terminal nodes. New references: PMID:31959004, PMID:32083975, PMID:37395136, PMID:39420976, clinicaltrials:NCT06024759, clinicaltrials:NCT03572569. Deliberately not cited and recorded in the entry notes: DOI:10.20944/preprints202507.1652.v1 (unpublished preprint duplicating criteria already covered by PMID:25443708), NCT04265040 (broad multi-cardiomyopathy cohort with no LVNC arm), and DOI:10.1101/2020.01.03.19015602 (medRxiv preprint of the already-cited PMID:33500567). One prose correction: the Cardiac Transplantation description previously stated that no PRDM16-specific transplant outcome data exist, which PMID:37395136 contradicts, so it was rewritten rather than left to rot beside the new evidence. Validation: just validate-disorders passed (schema, terms, references) with 122/122 snippets verified; compliance rose from 88.3 percent to 100 percent; check-duplicate-keys, check-entity-refs, check-causal-targets, check-qualifier-terms, check-enum-values, check-folded-hyphens, check-snippet-length, check-title-snippets, check-snippet-grading and check-environmental-evidence all pass with no new violations; model-scale-audit --strict exits 0. Uncited DOI caches written as a byproduct of the report's own reference-validation pass were pruned after re-deriving the cited-reference list, and snippet verification was re-run on the pruned tree.

Create: Left Ventricular Noncompaction 8 PRDM16 · 2026-08-18T04:36:41Z · View source

Created new dismech entry for left ventricular noncompaction 8 (LVNC8, MONDO:0014152, OMIM:615373, causal gene PRDM16 / hgnc:14000), resolving issue #8747. Duplicate preflight confirmed MONDO:0014152 was uncurated on origin/main, in all PRs, and in all issues before starting; a companion agent curated the distinct LVNC10/MYBPC3 entity (issue #8746) concurrently in a separate worktree. Literature base: direct PubMed search for PRDM16 plus LVNC/cardiomyopathy surfaced 9 primary-literature PMIDs (23768516 founding 1p36-deletion/PRDM16 report; 34915728 and 38113297 mouse/human mechanistic studies establishing PRDM16 as a compact-myocardium transcription factor that represses TGFB3 and restrains TGF-beta signaling; 27642787 iPSC-CM TGF-beta/PRDM16 study; 31965688 fetal presentation case; 35893073 pediatric cohort gene-frequency study; 39895316 WPW case; 40439125 review; 33500567 large rare-variant study already cited in Dilated_Cardiomyopathy_1AA.yaml). No dedicated GeneReviews chapter exists for LVNC8 specifically (searched PubMed TI:GeneReviews, no hit); NCBI MedGen (CUI C3809288) clinical-feature list was used as an OMIM/GeneReviews-equivalent phenotype baseline instead. Modeled a 7-node pathophysiology chain from PRDM16 loss-of-function variant through loss of compact-myocardium transcriptional identity, TGF-beta signaling dysregulation, impaired cardiomyocyte proliferation, to two parallel downstream branches (failed ventricular compaction; LV dilation and systolic dysfunction) converging on heart failure, arrhythmia, and thromboembolic risk, with conforms_to links into cardiomyopathy_maladaptive_remodeling#Ventricular Remodeling and #Structural Cardiac Impairment and Heart Failure (exact node names confirmed by grepping the module file). Resolved the noncompaction-vs-DCM nosological tension named in the issue via an explicit discussions entry (kind INTERPRETATION) citing PMID:23768516 (PRDM16 causal in both nonsyndromic LVNC and DCM cohorts) and PMID:33500567 (PRDM16 truncating variants LVNC-specific alongside MYH7/ACTN2), rather than silently picking one label; both the noncompaction and DCM phenotypes are curated as top-level Phenotype entries. Cross-referenced the polygenic Left_Ventricular_Noncompaction.yaml umbrella entry and Dilated_Cardiomyopathy.yaml / Dilated_Cardiomyopathy_1AA.yaml as differential diagnoses and related entries, and explicitly distinguished LVNC8 (single-gene, nonsyndromic) from 1p36 deletion syndrome (multigene, syndromic) as a second differential-diagnosis entry, since PRDM16 is the cardiomyopathy-critical gene within that contiguous-gene deletion. Deep research: ran just research-disorder falcon Left_Ventricular_Noncompaction_8 (Edison Scientific Literature provider, 633s runtime, citation_count 23, reference_validation confabulation_rate 0.0, 11/11 references verified, 8/11 on-topic). Ran just preflight-dr against MONDO:0014152 before using the report: verdict WARN (PRDM16 mentioned 57 times vs next-highest TBX20 3 times, a strong positive signal; the report's OMIM 605557 vs MONDO's OMIM xref 615373 flagged as a mismatch). Manually resolved the WARN per the SOP: confirmed via NCBI Gene / mygene.info that OMIM 605557 is PRDM16's own gene-locus MIM number, not a rival disease entity, while 615373 is the LVNC8 phenotype MIM number -- normal OMIM gene-MIM vs phenotype-MIM structure, not Named Entity Confusion. Cleared the report for use; no NEC found, no rival gene surfaced, and PRDM16's independent fame in brown-adipocyte biology was explicitly checked for and not present in the report. The falcon report's own content matched and confirmed the already-curated entry rather than surfacing materially new claims, so no additional falcon-sourced content was incorporated beyond the 9 PMIDs already found via direct PubMed search. Also cited the existing ClinGen PRDM16-dilated-cardiomyopathy Strong / autosomal-dominant gene-disease validity assertion (already cached from Dilated_Cardiomyopathy.yaml curation) for the genetic and inheritance sections, and one GEO dataset (geo:GSE307782, a PRDM16 hiPSC-cardiomyocyte knockdown/overexpression study; no evidence block, per the bulk-dataset convention, since no linked PMID exists yet). Validation performed and read to completion: just validate (schema pass, term validation pass, reference validation 34/34 snippets verified against cached references), just count-verified-snippets (34/34), just validate-terms (pass), and just validate-disorders -- the CI-equivalent batched pre-PR sweep -- (schema pass, term pass, 34/34 snippets verified). Additionally ran, to completion, a targeted pytest tests/test_data.py -k "conforms_to_module_node_references or subtype_foreign_keys or environmental_mechanism_targets or duplicate" sweep across the whole KB (6149 passed, 0 failed) confirming the new entry's conforms_to/foreign-key references do not break repository-wide invariants.

Falcon ▸

Left Ventricular Noncompaction 8 (LVNC8): Comprehensive Disease Report

Edison Scientific Literature 36 citations 2026-09-06T14:40:25.374206

Left Ventricular Noncompaction 8 (LVNC8): Comprehensive Disease Report

Executive summary and evidence boundaries

Left ventricular noncompaction 8 (LVNC8; MONDO:0014152) is the PRDM16-associated genetic subtype of left ventricular noncompaction. It is principally caused by heterozygous germline loss-of-function variants or deletions involving PRDM16, with haploinsufficiency as the best-supported mechanism. The cardiac phenotype ranges from isolated excessive left-ventricular trabeculation to noncompaction cardiomyopathy with dilation, systolic failure, fibrosis, arrhythmia, or conduction disease. Penetrance is incomplete and expression is highly variable.

A critical distinction is necessary: most epidemiologic, diagnostic, prognostic, and treatment evidence concerns LVNC of all genetic causes, not LVNC8 specifically. Imaging-defined hypertrabeculation alone is neither specific for PRDM16 disease nor necessarily pathological. A defensible LVNC8 diagnosis therefore requires a compatible phenotype plus a pathogenic/likely pathogenic PRDM16 variant or PRDM16-containing deletion.

Domain	PRDM16/LVNC8-specific finding	Evidence type	Knowledge-base annotation
Identity	LVNC8 is the PRDM16-associated form of left ventricular noncompaction; heterozygous loss-of-function and deletion evidence supports PRDM16 haploinsufficiency, although LVNC can also overlap dilated cardiomyopathy (DCM). (arndt2013finemappingof pages 4-5, mazzarotto2020thegeneticarchitecture pages 1-3, boudina2023prdm16deletionis pages 1-3)	Human genetic association; segregation; translational models	MONDO:0014152; gene: PRDM16; genetic disease; distinguish subtype-specific disease from broad LVNC morphology
Representative variants	Reported LVNC-associated variants include *c.1573dupC (p.Arg525Profs79), c.2104A>T (p.Lys702Ter), and p.Gln187Ter/Q187X**; these are germline protein-truncating variants expected to cause loss of function. (sun2023nonsensevariantprdm16q187x pages 1-3, arndt2013finemappingof pages 4-5)	Human cases; patient-derived iPSC cardiomyocytes; knock-in mouse	Variant classes: frameshift, nonsense; consequence: loss of function/haploinsufficiency; verify transcript and ClinVar classification before variant-level ingestion
Chromosomal lesion	Heterozygous 1p36 deletions encompassing PRDM16 increase cardiomyopathy risk, but neighboring deleted genes may modify the syndromic phenotype. In a combined cohort, cardiomyopathy occurred in 29.1% with versus 10.8% without PRDM16 deletion. (boudina2023prdm16deletionis pages 1-3)	Human retrospective cohort plus systematic review, n=134	Structural variant/CNV; 1p36 deletion syndrome; record PRDM16-containing deletions separately from isolated sequence variants
Inheritance	Sequence-variant LVNC8 is principally described as autosomal dominant with incomplete, age-dependent penetrance and variable expressivity; phenotypes include LVNC, DCM, or overlapping LVNC/DCM. (sun2023nonsensevariantprdm16q187x pages 10-11, arndt2013finemappingof pages 4-5, mazzarotto2020thegeneticarchitecture pages 1-3)	Human pedigrees and case series	AD inheritance; germline; variable expressivity; no established anticipation or founder effect
Key phenotypes	Excessive LV trabeculation/deep intertrabecular recesses, thin compact myocardium, LV systolic dysfunction or dilation, heart failure, fibrosis, arrhythmia, and conduction abnormalities; onset ranges from fetal/infantile to adult and severity is variable. (sun2023nonsensevariantprdm16q187x pages 1-3, arndt2013finemappingof pages 4-5, nam2020cardiacspecificinactivationof pages 1-5)	PRDM16-specific human cases and models	Suggested HPO: HP:0030682 left ventricular noncompaction; HP:0001635 congestive heart failure; HP:0001644 dilated cardiomyopathy; HP:0011675 arrhythmia; HP:0031546 myocardial fibrosis
Upstream mechanism	PRDM16 loss disrupts its transcriptional/chromatin-regulatory function, reducing specification and proliferation of compact-myocardial cardiomyocytes and permitting trabecular, atrial, neuronal-like, or conduction-cell transcriptional programs. (wu2022prdm16isa pages 11-13, wauwe2024prdm16determinesspecification pages 1-2)	Conditional mouse genetics; scRNA-seq; spatial transcriptomics; single-cell RNA+ATAC sequencing	GO suggestions: regulation of transcription, chromatin organization, cardiac muscle-cell differentiation, ventricular cardiac muscle development; CL: ventricular cardiomyocyte, cardiac conduction cell
TGF-β and tissue injury	PRDM16 binds TGFB2/TGFB3 regulatory regions and alters H3K4 methylation. Loss produces developmentally dependent TGF-β dysregulation, impaired proliferation, increased apoptosis, fibrosis, and hypertrophy; some causal links remain model-derived. (sun2023nonsensevariantprdm16q187x pages 1-3, sun2023nonsensevariantprdm16q187x pages 10-11, sun2023nonsensevariantprdm16q187x pages 11-13, nam2020cardiacspecificinactivationof pages 1-5)	Patient iPSC cardiomyocytes; knock-in/conditional mice; cardiomyoblast assays	GO: TGF-β receptor signaling, cardiomyocyte proliferation, apoptotic process, extracellular-matrix organization; cells: cardiomyocyte and cardiac fibroblast
Electrophysiology	Prdm16-null mouse hearts have prolonged QRS/QTc, fibrosis, and dysregulated KCNE1, SCN5A, CACNA1H, CACNA2D2, suggesting impaired Na+, K+, and Ca2+ homeostasis; TGF-β-receptor inhibition did not rescue conduction defects. (nam2020cardiacspecificinactivationof pages 1-5)	Mouse ECG, histology, qPCR, RNA-seq	GO: cardiac conduction, membrane depolarization, ion transmembrane transport; classify as mechanistic model evidence, not a proven universal human pathway
2023–2024 developments	The 2023 Q187X study linked human pediatric LVNC to impaired proliferation, apoptosis, and TGF-β dysregulation. A 2023 multi-omics study identified early sex-specific energetic abnormalities. In 2024, single-cell RNA+ATAC analysis showed loss of ventricular working-cardiomyocyte identity and distal conduction-system hyperplasia. (sun2023nonsensevariantprdm16q187x pages 1-3, wauwe2024prdm16determinesspecification pages 1-2, kuhnisch2023prdm16mutationdetermines pages 1-2)	Human/iPSC and mouse translational studies; transcriptomics, proteomics, metabolomics, scRNA+ATAC	Recent evidence strengthens developmental cell-identity and metabolic mechanisms but does not yet establish a targeted therapy
Metabolism	Monoallelic Prdm16-mutant mice showed reduced amino-acid, glycerol, glycolytic and TCA-cycle metabolites, low glutathione, increased IMP, male-specific triacylglyceride accumulation, reduced male fatty-acid use, and reduced female glucose use. (kuhnisch2023prdm16mutationdetermines pages 1-2)	Mouse multi-omics and computational metabolic modeling	GO: cellular respiration, glycolysis, TCA cycle, fatty-acid oxidation, glutathione metabolism, response to oxidative stress; model-only evidence
Diagnosis	Broad-LVNC fact: diagnosis integrates clinical context with echocardiography and CMR rather than morphology alone. Common thresholds include echocardiographic NC/C >2 and CMR NC/C ≥2.3; hypertrabeculation may be physiological in athletes or pregnancy. (martineztittonel2025leftventricularnoncompaction pages 5-7, NCT03572569 chunk 1, aung2020prognosticsignificanceof pages 1-2)	Imaging cohorts, reviews, registry criteria	Imaging phenotype plus function, ECG, family history, and genetics; use a cardiomyopathy panel including PRDM16, with CNV analysis; consider CMA for syndromic 1p36 deletion
Prognosis	Broad-LVNC fact: outcomes are driven more by LVEF than trabeculation burden. Across 2,501 patients, cardiovascular mortality was 1.92 and ventricular arrhythmia 2.17 per 100 person-years. PRDM16-specific: deletion was associated with death, transplant, or VAD (p=0.04). (boudina2023prdm16deletionis pages 1-3, aung2020prognosticsignificanceof pages 1-2)	Meta-analysis of observational cohorts; PRDM16 deletion cohort	Adverse markers: reduced LVEF, advanced NYHA class, ventricular tachycardia, fibrosis/LGE; subtype-specific survival estimates remain unavailable
Treatment	No PRDM16- or LVNC8-specific disease-modifying therapy exists. Broad-LVNC practice: phenotype-directed guideline therapy for heart failure and arrhythmia; anticoagulation for standard indications or documented thrombus/embolism; ICD according to systolic-function/arrhythmic risk; LVAD or transplantation for end-stage disease.	Extrapolated cardiomyopathy/heart-failure management; no subtype-specific randomized trial	NCIT suggestions: Pharmacotherapy, Anticoagulation Therapy, Implantable Cardioverter-Defibrillator, Ventricular Assist Device, Heart Transplantation
Models	Available systems include PRDM16-Q187X patient-derived iPSC cardiomyocytes, Q187X knock-in mice, cardiomyocyte-specific Prdm16 knockout mice, monoallelic Prdm16csp1/wt mice, and zebrafish knockdown. They reproduce impaired proliferation, apoptosis, noncompaction/compact-layer defects, dysfunction, fibrosis, conduction changes, and metabolic abnormalities to varying degrees. (sun2023nonsensevariantprdm16q187x pages 1-3, wu2022prdm16isa pages 11-13, nam2020cardiacspecificinactivationof pages 1-5, kuhnisch2023prdm16mutationdetermines pages 1-2)	In vitro human cells; mouse and zebrafish genetic models	Taxa: Homo sapiens, Mus musculus, Danio rerio; model limitations include dosage-, Cre-, developmental-stage-, and sex-dependent phenotypes
Uncertainty	PRDM16 truncating variants are enriched in LVNC, but penetrance, subtype prevalence, complete phenotype frequencies, modifiers, environmental interactions, protective factors, and variant-specific prognosis are not established. Morphologic LVNC alone is neither specific for LVNC8 nor necessarily pathological. (sun2023nonsensevariantprdm16q187x pages 11-13, mazzarotto2020thegeneticarchitecture pages 1-3, aung2020prognosticsignificanceof pages 1-2)	Genetic association and expert synthesis	Do not infer LVNC8 from imaging alone; require pathogenic/likely pathogenic PRDM16 evidence and phenotype correlation; retain VUS separately

Table: Concise evidence map for PRDM16-associated left ventricular noncompaction, separating subtype-specific findings from broader LVNC evidence. It summarizes genetics, mechanisms, phenotypes, diagnostics, prognosis, treatment, models, and ontology-ready annotations.

1. Disease information

Definition

LVNC is a ventricular myocardial phenotype characterized by excessive trabeculae, deep intertrabecular recesses communicating with the ventricular cavity, and a relatively thin compact epicardial layer. LVNC8 denotes the subset attributable to PRDM16 dysfunction. Large-scale genetic analysis found that many LVNC cases overlap genetically with dilated or hypertrophic cardiomyopathy, whereas protein-truncating variants in PRDM16, MYH7, and ACTN2 showed enrichment more specific to noncompaction. Thus, LVNC8 is best treated as a molecularly defined developmental cardiomyopathy rather than an imaging label alone. (mazzarotto2020thegeneticarchitecture pages 1-3)

Identifiers and synonyms

MONDO: MONDO:0014152, Left ventricular noncompaction 8.
Gene: PRDM16, PR/SET domain 16; chromosomal location 1p36.32.
Suggested OMIM mapping: the numbered phenotype is commonly represented as Left ventricular noncompaction 8; database release-specific OMIM numbers should be verified directly before production ingestion.
MeSH: no retrieved evidence established a dedicated LVNC8 MeSH descriptor; broader indexing commonly falls under cardiomyopathies.
ICD-10/ICD-11: no gene-specific LVNC8 code was identified. Coding generally uses an appropriate cardiomyopathy code, supplemented by a genetic diagnosis where supported.
Synonyms: PRDM16-related cardiomyopathy; PRDM16-associated noncompaction cardiomyopathy; PRDM16-associated LVNC; noncompaction cardiomyopathy due to PRDM16 haploinsufficiency; left ventricular hypertrabeculation/noncompaction, PRDM16-related.

This report synthesizes aggregated disease-level resources and published cohorts, not individual EHR records. Patient-level observations are used only where reported in primary case or family studies.

2. Etiology

Causal factors and genetic risk

The primary cause is a heterozygous germline loss-of-function variant in PRDM16 or a chromosome 1p36 deletion encompassing PRDM16. Foundational human variants included c.1573dupC (p.Arg525ProfsTer79), c.2104A>T (p.Lys702Ter), and c.2447A>G (p.Asn816Ser). These variants affected conserved residues or truncated the protein and were absent from 1000 Genomes and more than 6,400 Exome Sequencing Project controls. The study found greater than fourfold enrichment of novel nonsynonymous variants over expectation, with p=0.006. Published July 2013; DOI: 10.1016/j.ajhg.2013.05.015. (arndt2013finemappingof pages 4-5)

A large analysis of 840 LVNC cases and 125,748 gnomAD controls independently found PRDM16 truncating variants among the classes uniquely enriched in LVNC, supporting haploinsufficiency rather than a generic association with all cardiomyopathies. (mazzarotto2020thegeneticarchitecture pages 1-3)

The 2023 Q187X study reported two pediatric probands with PRDM16 loss-of-function variants; one had PRDM16 p.Gln187Ter (Q187X) and infant-onset heart failure. Its abstract states: “Novel loss-of-function PRDM16 variant impairs myocardial development resulting in noncompaction cardiomyopathy in humans and mice associated with altered TGF-β signaling.” Published December 2023; DOI: 10.1161/CIRCHEARTFAILURE.122.010351. (sun2023nonsensevariantprdm16q187x pages 1-3)

Chromosome 1p36 deletion

In a four-hospital retrospective cohort of 71 people with 1p36 deletion syndrome, cardiomyopathy occurred in 34.5% of individuals whose deletion included PRDM16 versus 7.7% when PRDM16 was retained, although this comparison did not reach significance (p=0.1). In the combined clinical and systematic-review cohort (n=134), the corresponding rates were 29.1% versus 10.8% (p=0.03). PRDM16 deletion was also associated with death, transplantation, or ventricular-assist-device support (p=0.04). Published August 2023; DOI: 10.1161/CIRCGEN.122.003912. (boudina2023prdm16deletionis pages 1-3)

Because 1p36 deletions can remove multiple genes, their syndromic manifestations cannot be attributed wholly to PRDM16. Sequence-variant LVNC8 and PRDM16-containing 1p36 deletion syndrome should therefore be represented as related but distinct knowledge-base entities.

Environmental, lifestyle, infectious, and protective factors

No toxin, infection, diet, smoking exposure, or occupational factor is known to cause molecularly defined LVNC8. Hemodynamic loading, pregnancy, and intensive exercise can produce acquired or physiological hypertrabeculation, creating an imaging phenocopy rather than PRDM16 disease. (mazzarotto2020thegeneticarchitecture pages 1-3, aung2020prognosticsignificanceof pages 1-2)

No validated protective PRDM16 allele, diet, medication, or lifestyle exposure has been demonstrated. A 2024 exploratory study proposed a potentially protective MYH7 SNV for broad LVNC, but this is neither replicated nor relevant enough to annotate as protective for LVNC8.

Gene–environment interaction

A formal PRDM16-by-environment interaction has not been established. It is plausible—but unproved—that pregnancy, athletic loading, hypertension, myocarditis, alcohol, or cardiotoxic exposure could unmask dysfunction in a genetically susceptible myocardium. Such factors should be documented clinically as possible modifiers, not recorded as established LVNC8 causes.

3. Phenotypes

Subtype-specific frequencies are unavailable because published PRDM16 cohorts are small. The following phenotype spectrum combines PRDM16 cases with clearly labeled broad-LVNC estimates.

Left ventricular noncompaction/hypertrabeculation — structural sign; congenital substrate, detectable prenatally through adulthood; severity variable. Suggested HPO: HP:0030682, Left ventricular noncompaction.
Thin or underdeveloped compact myocardium — imaging/pathologic sign; developmental and potentially progressive in functional consequence. Suggested HPO: HP:0030682, with a local morphology annotation if no more specific HPO term is available.
Dilated cardiomyopathy/LV dilation — sign; childhood or adult onset; may progress. Suggested HPO: HP:0001644, Dilated cardiomyopathy.
Reduced LV systolic function/heart failure — sign and symptom complex; ranges from absent to severe infantile or adult failure. Suggested HPO: HP:0001635, Congestive heart failure; HP:0012664, reduced ejection fraction.
Arrhythmia and conduction disease — palpitations, bradycardia, AV block, ventricular or supraventricular arrhythmia, and occasionally pre-excitation. Suggested HPO: HP:0011675, Arrhythmia; HP:0001662, bradycardia; HP:0001678, atrioventricular block; HP:0004308, ventricular arrhythmia.
Myocardial fibrosis — CMR or histologic sign, generally associated with worse function. Suggested HPO: myocardial fibrosis where available; GO:0030198 extracellular matrix organization.
Thromboembolism/stroke — downstream complication, especially with reduced function, atrial fibrillation, or intracardiac thrombus. Suggested HPO: HP:0002140 ischemic stroke; HP:0001907 thromboembolism.
Sudden cardiac arrest/death — uncommon but clinically important complication of malignant arrhythmia or severe cardiomyopathy.

For context, a pediatric LVNC cohort of 31 children—not restricted to PRDM16—reported heart-failure symptoms in 10/31 (32%), arrhythmia or AV-conduction abnormalities in 15/31 (48%), elevated NT-proBNP in 5/31 (16%), thromboembolism in 2/31 (6%), and death in 2/31 (6%). Sixteen children (52%) had an identified molecular variant, including two with PRDM16 variants. These rates must not be assigned directly to LVNC8. (piekutowskaabramczuk2022geneticprofileof pages 3-5)

Quality of life has not been quantified specifically for LVNC8 using EQ-5D, SF-36, or PROMIS. Symptomatic heart failure can impair exercise tolerance, schooling/employment, and activities of daily living; arrhythmic risk and inherited-disease surveillance add psychosocial burden.

4. Genetic and molecular information

Causal gene and protein

Gene: PRDM16; HGNC identifier should be verified against the current HGNC release before ingestion.
Protein: a nuclear zinc-finger transcriptional regulator containing a PR/SET domain, two zinc-finger DNA-binding regions, and transcriptional activation/repression domains. It also influences chromatin state and histone H3K4 methylation. (nam2020cardiacspecificinactivationof pages 1-5)
Disease mechanism: predominantly loss of function/haploinsufficiency.
Origin: germline. No evidence supports a recurrent somatic LVNC8 mechanism.

Variant classes and interpretation

Documented classes include nonsense, frameshift, splice-disrupting, missense, and multigene copy-number deletions. Protein-truncating variants provide the strongest class-level evidence. Each variant nevertheless requires current ACMG/AMP classification, transcript normalization, segregation review, and population-frequency assessment. A VUS must not establish LVNC8.

Population frequencies are variant-specific. The foundational truncating variants were absent from the cited historical controls. One later PRDM16 variant associated with LVNC/Wolff–Parkinson–White syndrome, rs201814961/ClinVar Variation ID 487607, was reported at approximately 0.03% in gnomAD, illustrating why rarity alone does not establish pathogenicity. (umapathi2025…geneticvariant pages 1-2, umapathi2025araregenetic pages 1-2)

Modifiers, epigenetics, and structural variation

No validated human modifier gene is established. Variable 1p36 deletion boundaries, additional cardiomyopathy variants, sex, and genetic background are plausible modifiers. PRDM16 itself changes chromatin accessibility and H3K4 methylation at target loci, but no diagnostic DNA-methylation signature has been validated. Large PRDM16-containing 1p36 deletions are the principal structural abnormality; no recurrent LVNC8-specific translocation, inversion, aneuploidy, or repeat expansion is known.

5. Environmental information

LVNC8 is not infectious or toxicologic, and it has no zoonotic transmission. Athletic remodeling, pregnancy, anemia/sickle-cell disease, and other loading states can mimic LVNC morphology and should be treated as differential-context variables. Smoking, alcohol excess, obesity, uncontrolled hypertension, and cardiotoxic drugs may worsen general myocardial health, but LVNC8-specific effect sizes are unavailable. (martineztittonel2025leftventricularnoncompaction pages 5-7, aung2020prognosticsignificanceof pages 1-2)

6. Mechanism and pathophysiology

Ordered causal chain

A heterozygous PRDM16 loss-of-function variant or deletion leads to reduced PRDM16 dosage and transcriptional/chromatin-regulatory activity.
Reduced PRDM16 activity leads to impaired ventricular working/compact-cardiomyocyte specification and permits inappropriate trabecular, atrial, neuronal-like, or conduction-cell programs. This is demonstrated primarily in mouse single-cell studies and inferred in humans. (wu2022prdm16isa pages 11-13, wauwe2024prdm16determinesspecification pages 1-2)
Abnormal cell identity leads to reduced compact-layer cardiomyocyte proliferation and, in some models, increased apoptosis, producing an underdeveloped compact myocardium. (sun2023nonsensevariantprdm16q187x pages 1-3, wu2022prdm16isa pages 11-13)
PRDM16 loss also leads to developmentally abnormal TGF-β regulation through TGFB2/TGFB3 promoter occupancy and altered H3K4 methylation; the direction depends on developmental stage. (sun2023nonsensevariantprdm16q187x pages 10-11, sun2023nonsensevariantprdm16q187x pages 11-13)
These developmental defects lead to persistent trabeculation/noncompaction and ventricular wall abnormality.
Branch A: altered myocardial structure and energetics lead to hypoplasia or dilation, systolic dysfunction, remodeling, fibrosis, and heart failure. (boudina2023prdm16deletionis pages 1-3, kuhnisch2023prdm16mutationdetermines pages 1-2)
Branch B: conduction-system fate expansion, ion-channel dysregulation, and fibrosis lead to slowed conduction, prolonged QRS/QTc, arrhythmia, and possible sudden death. The detailed ion mechanism is demonstrated in mice and remains inferential in human LVNC8. (nam2020cardiacspecificinactivationof pages 1-5, wauwe2024prdm16determinesspecification pages 1-2)
Branch C: ventricular dysfunction, recess-associated stasis, and atrial arrhythmia may lead to intracardiac thrombosis and systemic embolism; this is broad-LVNC inference rather than a PRDM16-specific demonstration.

Cellular identity and advanced profiling

A 2022 cardiomyocyte-specific knockout study combined scRNA-seq with spatial transcriptomics. LV compact cardiomyocytes lost compact-layer markers and acquired trabecular or even neuronal-like signatures. PRDM16 appeared to cooperate with LV-enriched TBX5 and HAND1. Importantly, noncompaction and dilation were separable: both ventricles could show noncompaction, while dilation and proliferative defects were LV-predominant. (wu2022prdm16isa pages 11-13)

A study published online 20 September 2024 used combined single-cell RNA and ATAC sequencing. PRDM16 loss opposed ventricular working-cardiomyocyte identity, permitted atrial and conduction fates, and produced distal ventricular-conduction-system hyperplasia, abnormal electrophysiology, contractile dysfunction, and premature death. DOI: 10.26508/lsa.202402719. (wauwe2024prdm16determinesspecification pages 1-2)

Suggested cell terms: CL:0000746 cardiac muscle cell/cardiomyocyte, ventricular working cardiomyocyte, trabecular cardiomyocyte, Purkinje/conduction-system cell, cardiac fibroblast, coronary arterial endothelial cell, and vascular smooth-muscle cell. Suggested processes: GO:0055008 cardiac muscle tissue development; GO:0007507 heart development; GO:0048738 cardiac muscle tissue development; GO:0006355 regulation of transcription; GO:0006338 chromatin remodeling; GO:0060048 cardiac muscle contraction; GO:0061337 cardiac conduction.

TGF-β, apoptosis, fibrosis, and ion homeostasis

Patient-derived Q187X iPSC cardiomyocytes showed significantly impaired proliferation and increased apoptosis with dysregulation of cardiac-maturation and TGF-β-associated transcripts. Homozygous Q187X mice had underdeveloped compact myocardium and embryonic lethality; heterozygotes had smaller ventricles, fibrosis, and age-dependent loss of TGF-β expression. (sun2023nonsensevariantprdm16q187x pages 1-3)

Cardiac-specific Prdm16-null mice had prolonged QRS and QTc, cardiomyocyte hypertrophy, and fibrosis, with increased Ctgf, Timp1, Acta2, Tgfb1–3, and phosphorylated SMAD2. RNA-seq identified dysregulated Kcne1, Scn5a, Cacna1h, and Cacna2d2, implicating Na+, K+, and Ca2+ homeostasis. TGF-β-receptor inhibition did not rescue conduction, suggesting a parallel electrophysiologic pathway rather than conduction disease being merely secondary to TGF-β activation. (nam2020cardiacspecificinactivationof pages 1-5)

Metabolic multi-omics

A 2023 transcriptomic, proteomic, metabolomic, lipidomic, and computational study of heterozygous Prdm16 mice found hypoplastic hearts and reduced systolic performance, worse in females. Mutant hearts had reduced amino-acid, glycerol, glycolytic, and tricarboxylic-acid-cycle metabolites; reduced glutathione and increased inosine monophosphate suggested oxidative stress and disturbed energetics. Male hearts accumulated triacylglycerides and showed reduced modeled fatty-acid use, whereas females showed lower glucose use. PYROXD2 and PBXIP1 were upregulated. The authors concluded that “metabolic dysregulation is an early event in the PRDM16 associated cardiac pathology.” Published online 16 October 2023; DOI: 10.1093/cvr/cvad154. These are model findings, not validated human biomarkers. (kuhnisch2023prdm16mutationdetermines pages 1-2)

Immune or autoimmune mechanisms, reproducible human proteomic biomarkers, and subtype-specific circulating metabolomic signatures have not been established.

7. Anatomical structures affected

The principal organ is the heart (UBERON:0000948), particularly the left ventricle (UBERON:0002084) and its myocardium. The apical and mid-inferolateral segments are commonly involved in broad LVNC, although distribution is variable. Biventricular noncompaction can occur, so the label “left ventricular” does not exclude right-ventricular trabecular abnormalities. (wu2022prdm16isa pages 11-13, aung2020prognosticsignificanceof pages 1-2)

Affected tissues and cells include compact and trabecular myocardium, ventricular cardiomyocytes, conduction-system cardiomyocytes, cardiac fibroblasts, and potentially coronary vascular cells. Relevant subcellular compartments are the nucleus/chromatin, sarcomeric/contractile apparatus, plasma membrane ion-channel complexes, and mitochondria. PRDM16 is predominantly nuclear in cardiomyocytes and cardiac interstitial cells. (arndt2013finemappingof pages 4-5, nam2020cardiacspecificinactivationof pages 1-5)

Secondary organs may be affected by heart-failure hypoperfusion or thromboembolism, especially brain, kidney, liver, and lung. There is no meaningful left-right body lateralization beyond predominant involvement of the left cardiac ventricle.

8. Temporal development

The initiating lesion is germline and the developmental substrate is congenital, but clinical onset ranges from fetal or infantile disease to asymptomatic adulthood. Severe biallelic disruption is embryonically lethal in mouse models; heterozygous human disease can cause infant-onset heart failure or remain mild for decades. (sun2023nonsensevariantprdm16q187x pages 1-3, sun2023nonsensevariantprdm16q187x pages 10-11)

The course is chronic and lifelong but highly variable: stable morphology with preserved function, progressive ventricular dysfunction, episodic arrhythmia, or advanced heart failure may occur. Critical periods include embryonic compact-myocardium specification, infancy/childhood in severe disease, puberty and growth, pregnancy, and periods of high hemodynamic demand. True remission of the causal genotype does not occur; ventricular function may improve with heart-failure therapy, and loading-related hypertrabeculation can regress when it is a phenocopy rather than LVNC8.

9. Inheritance and population

Inheritance

The usual pattern is autosomal dominant, with incomplete, age-dependent penetrance and variable expressivity. Reported expressions include isolated LVNC, DCM, mixed LVNC/DCM, preserved-function hypertrabeculation, and conduction disease. No evidence supports genetic anticipation. Germline mosaicism is theoretically possible but not quantified. No reproducible founder variant or consanguinity effect is established. Carrier frequency cannot be estimated because variant pathogenicity and penetrance remain uncertain.

Sex may modify severity. In PRDM16-deleted 1p36 cases, cardiomyopathy occurred in 34.5% of females versus 16.7% of males, but the difference was not significant (p=0.2). Female knockout mice had more severe dysfunction, fibrosis, and mortality (p=0.0003), providing biological support but not a definitive human sex-risk estimate. (boudina2023prdm16deletionis pages 1-3)

Epidemiology

No prevalence or incidence estimate exists for molecularly confirmed LVNC8. For adult LVNC of all causes, a 2024 systematic review/meta-analysis reported pooled prevalence of 0.5%, with CMR detection of 1.3%; estimates across studies ranged from 0.014% to 14.79%, illustrating major ascertainment and criteria effects. Mortality was 12% and transplantation 7%. Published online 16 September 2024; DOI: 10.14740/cr1673. (llerenavelastegui2024prevalenceclinicalmanifestations pages 1-2)

In an earlier meta-analysis of 2,501 LVNC patients, mean age was 46 years and the male:female ratio was 1.7:1. These figures cannot be assumed for LVNC8. (aung2020prognosticsignificanceof pages 1-2)

1p36 deletion syndrome occurs in approximately 1 in 5,000 newborns, but only a subset of deletions includes PRDM16 and only a subset of those individuals develops cardiomyopathy. (boudina2023prdm16deletionis pages 1-3)

No validated ethnic or geographic enrichment of isolated PRDM16-LVNC8 has been established.

10. Diagnostics

Clinical evaluation

Evaluation should include three-generation pedigree, symptoms, examination, 12-lead ECG, ambulatory ECG, echocardiography, and CMR when feasible. Exercise testing is useful for functional capacity and exertional arrhythmia. NT-proBNP/troponin can characterize heart failure or injury but are not diagnostic for LVNC8. Biopsy is not routinely required.

Common morphology thresholds include:

Chin echocardiographic criterion: X/Y ≤0.5 in diastole.
Jenni criterion: noncompacted/compacted (NC/C) ratio >2 in systole, with a two-layer structure and perfused recesses.
Stöllberger criterion: at least three prominent trabeculae apical to papillary muscles, perfused recesses, and often NC/C >2.
Petersen CMR criterion: NC/C ≥2.3 in end-diastole.
Jacquier CMR criterion: trabeculated mass >20% of total LV mass. (martineztittonel2025leftventricularnoncompaction pages 5-7)

These are not interchangeable and can overdiagnose healthy athletes, pregnancy-related remodeling, and some ancestries. The contemporary expert position is to integrate morphology with ventricular size/function, fibrosis, ECG abnormalities, symptoms, family history, congenital/syndromic features, and genotype. In a pediatric cohort, median echocardiographic NC/C was 2.80 and median CMR NC/C 3.09; CMR confirmed all 25 evaluable echocardiographic cases. (piekutowskaabramczuk2022geneticprofileof pages 3-5)

Genetic testing strategy

Perform a validated cardiomyopathy panel containing PRDM16 plus established LVNC/DCM/HCM and arrhythmia genes, with deletion/duplication analysis.
Use exome or genome sequencing when panel testing is negative and suspicion remains high, particularly for pediatric, syndromic, or familial disease.
Use chromosomal microarray when developmental delay, dysmorphism, seizures, congenital anomalies, or growth abnormalities suggest 1p36 deletion syndrome.
Confirm reportable variants and test parents/relatives for segregation.
RNA analysis may clarify suspected splice variants, but it is not yet routine.
Karyotype/FISH may characterize a known structural rearrangement but are less sensitive than CMA for small 1p36 deletions.
Mitochondrial DNA and repeat-expansion testing are not specifically indicated unless the broader phenotype suggests those disorders.

Differential diagnosis

Rule out physiological athlete’s heart, pregnancy-associated hypertrabeculation, sickle-cell/anemia-associated remodeling, DCM/HCM with secondary trabeculation, myocarditis, ischemic or hypertensive remodeling, apical hypertrophic cardiomyopathy, endocardial fibroelastosis, endomyocardial fibrosis, cardiac tumors or thrombus, congenital heart disease, Barth syndrome/TAZ disease, mitochondrial disease, neuromuscular disorders, and HCN4/RYR2-associated arrhythmic LVNC. (martineztittonel2025leftventricularnoncompaction pages 5-7, aung2020prognosticsignificanceof pages 1-2)

Screening

Cascade screening of first-degree relatives should combine genetic testing for the familial pathogenic variant with ECG and cardiac imaging. Genotype-positive/phenotype-negative relatives require longitudinal surveillance because penetrance may be age-dependent. There is no population or newborn LVNC8 screening program.

11. Outcome and prognosis

LVNC8-specific survival curves are unavailable. In the broad-LVNC meta-analysis of 28 studies and 2,501 patients followed for a median 2.9 years, event rates per 100 person-years were:

cardiovascular mortality 1.92 (95% CI 1.54–2.30);
all-cause mortality 2.16;
stroke/systemic embolism 1.54;
heart-failure admission 3.53;
transplantation 1.24;
ventricular arrhythmia 2.17;
cardiac-device implantation 2.66. (aung2020prognosticsignificanceof pages 1-2)

Cardiovascular mortality was similar to DCM (OR 1.10, 95% CI 0.18–6.67). The strongest conclusion was that LVEF, not trabeculation burden, drove adverse outcomes. Reduced LVEF, NYHA III/IV symptoms, ventricular tachycardia, dilation, and CMR late gadolinium enhancement/fibrosis are therefore more useful prognostic markers than NC/C ratio alone. (llerenavelastegui2024prevalenceclinicalmanifestations pages 1-2, aung2020prognosticsignificanceof pages 1-2)

PRDM16 deletion conferred increased risk of death, transplantation, or VAD in the 2023 cohort. Severe pediatric onset, marked systolic dysfunction, malignant arrhythmia, and fibrosis should be regarded as adverse indicators, although no validated PRDM16-specific risk calculator exists. (boudina2023prdm16deletionis pages 1-3)

12. Treatment

No approved PRDM16-restoring, gene-editing, RNA, cell, or TGF-β-targeted therapy exists. Management is phenotype-directed and extrapolated from heart-failure and arrhythmia guidelines.

Heart failure: guideline-directed therapy according to age and phenotype, generally including an ACE inhibitor/ARB or ARNI, evidence-based beta-blocker, mineralocorticoid-receptor antagonist, SGLT2 inhibitor in eligible patients, and diuretics for congestion.
Arrhythmia: beta-blocker or other antiarrhythmic therapy selected by rhythm and ventricular function; catheter ablation when appropriate.
ICD: standard primary- or secondary-prevention indications based on LVEF, sustained VT/VF, prior arrest, and individualized genetic/fibrotic risk—not trabeculation alone.
Anticoagulation: indicated for atrial fibrillation, intracardiac thrombus, previous systemic embolism, or other conventional high-risk contexts. Routine anticoagulation solely for morphology is not supported.
Advanced failure: cardiac resynchronization when standard criteria are met; LVAD or heart transplantation for refractory end-stage disease.
Supportive care: individualized exercise advice, vaccination and infection prevention as for other cardiomyopathies, pregnancy counseling, psychosocial support, and cardiac rehabilitation when stable.

Suggested NCIt intervention concepts: Pharmacotherapy; Angiotensin-Converting Enzyme Inhibitor; Beta-Adrenergic Blocker; Anticoagulation Therapy; Catheter Ablation; Implantable Cardioverter-Defibrillator; Cardiac Resynchronization Therapy; Ventricular Assist Device; Heart Transplantation.

Current research implementation

No retrieved interventional trial tested an LVNC8-specific treatment. Active work is registry-based:

NCT06024759, recruiting, estimated 500 adults, follows LVNC for 10 years to identify genetic, strain, PVC/NSVT, dysfunction, and ICD-risk predictors; start 1 September 2023, estimated completion 2033. ClinicalTrials.gov. (NCT06024759 chunk 1)
NCT04265040 (TORCH-Plus), recruiting, estimated 2,040 participants, integrates deep phenotyping, genomics, inflammation, fibrosis, biomarkers, and outcomes across cardiomyopathies including rare LVNC; estimated completion December 2027. ClinicalTrials.gov. (NCT04265040 chunk 1)
NCT03572569 (RIKADA) is a prospective family-based pediatric cardiomyopathy study, estimated 200 participants, incorporating ECG/Holter, exercise testing, echo, CMR, laboratory testing, and genetics. Registry status is currently “unknown,” with last known status recruiting. ClinicalTrials.gov. (NCT03572569 chunk 1)

13. Prevention

Primary prevention of a de novo or inherited PRDM16 variant is not available. Reproductive options after genetic counseling include prenatal diagnosis and preimplantation genetic testing when a familial pathogenic variant is known; counseling must emphasize incomplete penetrance and variable expressivity.

Secondary prevention consists of cascade genetic testing, baseline ECG/echo, periodic surveillance of genotype-positive relatives, ambulatory rhythm monitoring when indicated, and early treatment of ventricular dysfunction or arrhythmia. Tertiary prevention includes guideline-directed heart-failure therapy, embolic-risk management, ICD use under conventional criteria, avoidance of cardiotoxic exposures, and timely referral for advanced-heart-failure care.

No vaccine or infectious prophylaxis prevents LVNC8. General vaccination and prompt treatment of infections may reduce cardiovascular decompensation but are not disease-specific.

14. Other species and natural disease

Human: Homo sapiens, NCBI Taxonomy 9606; naturally occurring PRDM16 variants and deletions cause LVNC/DCM.
Mouse: Mus musculus, Taxonomy 10090; engineered Prdm16 loss produces noncompaction, compact-layer defects, conduction abnormalities, fibrosis, metabolic dysfunction, and sex-biased severity.
Zebrafish: Danio rerio, Taxonomy 7955; experimental prdm16 knockdown reduces heart rate and cardiac output and impairs cardiomyocyte proliferation. (nam2020cardiacspecificinactivationof pages 1-5)

No well-established naturally occurring veterinary LVNC8 syndrome or breed predisposition was identified. There is no transmission or zoonotic potential. The conserved cardiac expression and phenotype across vertebrates support evolutionary conservation of PRDM16-dependent myocardial development, although zebrafish cardiac anatomy and regenerative capacity limit direct clinical extrapolation.

15. Model organisms and experimental systems

Available models

Patient-derived PRDM16-Q187X iPSC cardiomyocytes: impaired proliferation, increased apoptosis, and TGF-β/cardiac-maturation transcriptional abnormalities. Strength: human genetic background. Limitation: immature in-vitro cardiomyocytes and absent organ-level loading. (sun2023nonsensevariantprdm16q187x pages 1-3)
Prdm16-Q187X knock-in mouse: homozygotes show compact-layer underdevelopment and embryonic lethality; heterozygotes show milder underdevelopment, fibrosis, and age-dependent signaling changes. Strength: allelic fidelity; limitation: mouse dosage effects differ from humans. (sun2023nonsensevariantprdm16q187x pages 1-3, sun2023nonsensevariantprdm16q187x pages 10-11)
Cardiomyocyte-specific Prdm16 knockout mouse: recapitulates LV-predominant dilation/dysfunction, noncompaction, identity switching, conduction abnormalities, hypertrophy, and fibrosis. Useful for developmental timing and cell-autonomous effects; results depend on Cre driver and deletion timing. (wu2022prdm16isa pages 11-13, nam2020cardiacspecificinactivationof pages 1-5)
Prdm16csp1/wt systemic heterozygous mouse: models monoallelic human loss and early sex-specific metabolic dysfunction; useful for multi-omics and preclinical metabolism studies. (kuhnisch2023prdm16mutationdetermines pages 1-2)
Zebrafish morpholino/knockdown: suitable for rapid developmental and cardiac-output assays but incompletely models mammalian ventricular compaction.
H9c2 cardiomyoblasts: demonstrated PRDM16 occupancy/regulation at TGFB promoters and H3K4 effects; limited by their rat, nonadult-cardiomyocyte identity. (sun2023nonsensevariantprdm16q187x pages 11-13)

No validated human cardiac organoid, large-animal, or natural veterinary PRDM16-LVNC8 model was identified in the retrieved literature.

Evidence gaps and knowledge-base cautions

Molecularly confirmed LVNC8 prevalence, incidence, penetrance, and age-specific natural history remain unknown.
Human phenotype frequencies cannot be inferred from broad LVNC cohorts.
Variant-specific risks require current ClinVar/ClinGen and population-database review; historical “mutation” labels should not automatically be converted to pathogenic.
Imaging hypertrabeculation alone must not be equated with cardiomyopathy or LVNC8.
TGF-β, metabolic, and conduction mechanisms are compelling but predominantly model-derived; none yet supports targeted clinical therapy.
No validated protective factor, pharmacogenomic rule, molecular biomarker, epigenetic diagnostic, or disease-modifying treatment exists.

Overall, the strongest current model is that PRDM16 haploinsufficiency disrupts ventricular/compact-cardiomyocyte identity, proliferation, chromatin regulation, developmental TGF-β signaling, electrophysiology, and energy metabolism, producing a variably penetrant spectrum from isolated hypertrabeculation to severe noncompaction/dilated cardiomyopathy.

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(umapathi2025…geneticvariant pages 1-2): KK Umapathi, SB Schmidt, and U Kohli. … genetic variant in prdm16 is associated with wolff–parkinson–white syndrome with complex accessory pathway characteristics and left ventricular non-compaction …. Unknown journal, 2025.
(umapathi2025araregenetic pages 1-2): KK Umapathi, SB Schmidt, and U Kohli. A rare genetic variant in prdm16 is associated with wolff–parkinson–white syndrome with complex accessory pathway characteristics and left ventricular non …. Unknown journal, 2025.
(llerenavelastegui2024prevalenceclinicalmanifestations pages 1-2): Jordan Llerena-Velastegui, Almendra Lopez-Usina, and Camila Mantilla-Cisneros. Prevalence, clinical manifestations, and adverse outcomes of left ventricular noncompaction in adults: a systematic review and meta-analysis. Oct 2024. URL: https://doi.org/10.14740/cr1673, doi:10.14740/cr1673. This article has 6 citations.
(NCT06024759 chunk 1): Predictors of Risk in Left Ventricular Non-Compaction. London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's. 2023. ClinicalTrials.gov Identifier: NCT06024759
(NCT04265040 chunk 1): Benjamin Meder. DZHK TORCH-Plus is a Registry for Patients With Cardiomyopathies and Serves as Source for Cardiovascular Research Studies. University Hospital Heidelberg. 2020. ClinicalTrials.gov Identifier: NCT04265040

Artifacts

Edison artifact artifact-00

Reference Validation

Checked with linkml-reference-validator 0.2.1.

Outcome	Count
References checked	13
Resolved	13
Unresolved (possible confabulation)	0
Unverifiable	0
References weighed for topical relevance	13
On topic	10
Off topic	0

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome	Count
Terms checked	23
Resolved	23
Unresolved (possible confabulation)	0
Obsolete	0
Unverifiable	0
Terms whose name was checked	3
Terms named correctly	2
Terms named as a different term	1

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

MONDO:0014152 (4 mentions) - the report calls it "if available"; MONDO calls it left ventricular noncompaction 8

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OpenScientist Report

Mappings

Inheritance

Discussions and Knowledge Gaps

Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Medical Actions

Diagnosis

Prevalence

Differential Diagnoses

Related Datasets

Clinical Trials

Experimental Models

Animal Models

Source YAML

References & Deep Research

References

Deep Research

Left Ventricular Noncompaction 8 (LVNC8): Comprehensive Disease Report

Executive summary and evidence boundaries

1. Disease information

Definition

Identifiers and synonyms

2. Etiology

Causal factors and genetic risk

Chromosome 1p36 deletion

Environmental, lifestyle, infectious, and protective factors

Gene–environment interaction

3. Phenotypes

4. Genetic and molecular information

Causal gene and protein

Variant classes and interpretation

Modifiers, epigenetics, and structural variation

5. Environmental information

6. Mechanism and pathophysiology

Ordered causal chain

Cellular identity and advanced profiling

TGF-β, apoptosis, fibrosis, and ion homeostasis

Metabolic multi-omics

7. Anatomical structures affected

8. Temporal development

9. Inheritance and population

Inheritance

Epidemiology

10. Diagnostics

Clinical evaluation

Genetic testing strategy

Differential diagnosis

Screening

11. Outcome and prognosis

12. Treatment

Current research implementation

13. Prevention

14. Other species and natural disease

15. Model organisms and experimental systems

Available models

Evidence gaps and knowledge-base cautions

Artifacts

Reference Validation

Term Validation

Terms the report names something else