Histiocytoid Cardiomyopathy: Comprehensive Disease-Characteristics Report

Executive summary

Histiocytoid cardiomyopathy (HC) is an exceptionally rare, usually infantile myocardial/conduction-system disorder characterized by multifocal aggregates of enlarged, pale, mitochondria-rich cardiomyocytes with Purkinje/conduction-cell-like features. Although historically classified as a hamartoma or cardiac tumor, current molecular and ultrastructural evidence more strongly supports a mitochondrial cardiomyopathy with marked arrhythmogenicity. Fewer than 150 cases had been reported in the literature by the 2015 WHO-era review; consequently, nearly all quantitative evidence comes from aggregated case reports and small retrospective series rather than population registries or electronic-health-record cohorts. Most recognized patients present in the first year of life with ventricular tachyarrhythmia, heart failure, cardiac arrest, or sudden death. More than one-third reportedly have additional cardiac or extracardiac anomalies. (burke2016the2015who pages 2-3)

The strongest established molecular association is with NDUFB11, an X-chromosomal nuclear gene encoding an accessory subunit of mitochondrial respiratory-chain complex I. Patient-tissue studies show that pathogenic NDUFB11 variants can disrupt RNA splicing, eliminate or reduce NDUFB11 protein, impair complex-I assembly and activity, and alter respiratory supercomplexes. However, HC remains genetically heterogeneous or unsolved in many historical cases; an NDUFB11 result should therefore not be treated as necessary for diagnosis. (OpenTargets Search: histiocytoid cardiomyopathy-NDUFB11, amategarcia2023anovelmutation pages 6-8, amategarcia2023anovelmutation pages 5-6)

Table: This table condenses the main evidence-based facts for histiocytoid cardiomyopathy, including core phenotype, genetics, mechanism, anatomy, diagnostics, treatment categories, and evidence limitations. It is designed for rapid knowledge-base curation with ontology term suggestions and citation-backed confidence notes.

1. Disease information

Definition and classification

HC is a rare pediatric cardiomyopathy in which abnormal myocardial cells resemble histiocytes by light microscopy but are actually modified cardiomyocytes, often interpreted as conduction-system/Purkinje-like cells. Lesions are usually multifocal and occur in myocardium and endocardium, particularly the ventricles and atrioventricular or sinoatrial nodal regions. This localization explains the disproportionate burden of malignant ventricular arrhythmia. (burke2016the2015who pages 2-3)

The designation “tumor” is historical and potentially misleading: lesions are non-metastatic, and genetic, biochemical, and ultrastructural findings support a developmental/mitochondrial cardiomyopathy rather than a conventional neoplasm.

Identifiers and synonyms

• MONDO: MONDO:0010771.
• Open Targets disease–target association: MONDO:0010771–NDUFB11 (ENSG00000147123), based on five underlying evidence records in the retrieved database result. (OpenTargets Search: histiocytoid cardiomyopathy-NDUFB11)
• Common names: histiocytoid cardiomyopathy; infantile histiocytoid cardiomyopathy; oncocytic cardiomyopathy; infantile xanthomatous cardiomyopathy; arachnocytosis of the myocardium; Purkinje-cell hamartoma/dysplasia; conduction-system hamartoma; cardiac hamartoma.
• OMIM/Orphanet/MeSH/ICD: No disease-specific OMIM, Orphanet, MeSH, ICD-10, or ICD-11 identifier was verified in the retrieved evidence. Coding generally falls under broader cardiomyopathy, cardiac-arrhythmia, congenital-heart-disease, or cardiac-tumor categories; such mappings should be labeled approximate rather than equivalent.

Evidence granularity

The disease description is an aggregated disease-level synthesis assembled predominantly from published individual cases, autopsy material, small pathology series, and a historical HC registry. It is not based on a large EHR-derived cohort. This distinction matters because ascertainment is strongly biased toward lethal, surgically treated, or pathologically confirmed cases.

2. Etiology, risk, and protective factors

Causal factors

The leading cause is genetic mitochondrial respiratory-chain dysfunction. NDUFB11 is the principal established nuclear gene. Pathogenic variants cause deficient complex-I assembly/function and can produce HC, hypertrophic cardiomyopathy, left-ventricular noncompaction, sideroblastic anemia, or microphthalmia with linear skin defects syndrome. Open Targets identifies NDUFB11 as the sole associated target returned for MONDO:0010771. (OpenTargets Search: histiocytoid cardiomyopathy-NDUFB11, amategarcia2023anovelmutation pages 1-2)

A sporadic mitochondrial-DNA m.8344A>G MERRF-associated case has also been published, but this is isolated evidence and does not establish a common cause. Reports involving other genes, including possible ion-channel modifiers, should presently be regarded as candidate or case-level associations rather than validated HC genes.

Risk factors and modifiers

• Sex and X chromosome: Historical HC has a strong female predominance, while severe hemizygous NDUFB11 loss can be lethal in males. This apparently paradoxical distribution likely reflects variant-specific viability, X-linked biology, and ascertainment.
• X-chromosome inactivation: Female penetrance is modified by tissue-specific X-inactivation. In one 2023 family, clinically protected carrier women had skewing of 78:22 and 80:20, preferentially inactivating the variant-bearing chromosome. Conversely, unfavorable skewing was proposed to explain severe disease in a female neonate. (amategarcia2023anovelmutation pages 5-6, amategarcia2023anovelmutation pages 8-9, tariq2024casereportsevere pages 1-2)
• Family history: X-linked recurrence is possible, but de novo variants and apparently sporadic disease occur.
• Congenital anomalies: More than one-third of reported children had additional cardiac or extracardiac anomalies, but these are associated manifestations, not demonstrated causal exposures. (burke2016the2015who pages 2-3)

No reproducible environmental, dietary, toxic, occupational, infectious, lifestyle, or maternal exposure has been established. No validated genetic or environmental protective factor exists apart from the inferred protection conferred by favorable X-inactivation in some heterozygous women. No gene–environment interaction has been demonstrated.

3. Phenotypes

Core cardiac manifestations

1. Ventricular tachyarrhythmia—often severe, episodic, treatment-resistant, and capable of causing cardiac arrest or sudden death. Suggested HPO: Ventricular tachycardia, Ventricular arrhythmia, Cardiac arrest.
2. Sudden cardiac death, frequently during infancy and occasionally the first recognized manifestation. Suggested HPO: Sudden cardiac death.
3. Cardiomyopathy morphology—hypertrophic, dilated, or noncompaction phenotypes can accompany the histiocytoid lesion. Mitochondrial cardiomyopathy literature describes reduced fractional shortening and relatively concentric hypertrophy, with the worst mortality among patients diagnosed during the first year. Suggested HPO: Hypertrophic cardiomyopathy, Dilated cardiomyopathy, Left ventricular noncompaction, Reduced left ventricular systolic function. (adorisio2025mitochondrialcardiomyopathiesnavigating pages 3-4)
4. Heart failure—severity ranges from absent/asymptomatic childhood disease to rapidly progressive neonatal failure. Suggested HPO: Heart failure, Cardiomegaly, Poor cardiac output. (adorisio2025mitochondrialcardiomyopathiesnavigating pages 3-4, tariq2024casereportsevere pages 1-2)
5. Conduction/pre-excitation abnormalities—conduction-system localization makes bradyarrhythmia, conduction block, ectopy, and Wolff–Parkinson–White-like presentations biologically plausible and reported in case literature. Suggested HPO: Cardiac conduction abnormality, Ventricular premature beat, Pre-excitation syndrome.

Metabolic and syndromic manifestations

Lactic acidosis, elevated lactate/pyruvate ratio, failure to thrive, hypotonia/myopathy, epilepsy, sideroblastic anemia, microphthalmia, and linear skin defects occur in parts of the broader NDUFB11 spectrum but are not universal features of pathology-defined HC. A 2024 female neonate had a lactate/pyruvate ratio of 67.5. (amategarcia2023anovelmutation pages 1-2, tariq2024casereportsevere pages 2-3)

Suggested HPO terms include Lactic acidosis, Elevated circulating lactate concentration, Failure to thrive, Muscular hypotonia, Seizure, Sideroblastic anemia, Microphthalmia, and Aplasia cutis/linear skin defect as phenotype-appropriate.

Frequency, progression, and quality of life

Reliable phenotype percentages are unavailable. The most defensible qualitative frequencies are: infantile onset—common; ventricular arrhythmia/sudden death—common and characteristic; extracardiac or additional cardiac anomalies—>33% in the WHO review; cardiomyopathy morphology and heart failure—variable. (burke2016the2015who pages 2-3)

No HC-specific EQ-5D, SF-36, PROMIS, neurobehavioral, or caregiver-burden studies were found. Survivors may face recurrent hospitalization, medication burden, implanted devices, ablation or transplantation, and substantial restrictions related to arrhythmic risk.

4. Genetic and molecular information

Principal causal gene

NDUFB11—NADH:ubiquinone oxidoreductase subunit B11; Xp11.23; Ensembl ENSG00000147123. It encodes an approximately 17.3-kDa accessory component of the membrane/P module of mitochondrial complex I. (OpenTargets Search: histiocytoid cardiomyopathy-NDUFB11, amategarcia2023anovelmutation pages 6-8, tariq2024casereportsevere pages 2-3)

Documented recent variants

• c.338G>A, initially predicted p.(Arg113Lys): hemizygous, inherited from the mother, and classified likely pathogenic under ACMG/AMP criteria. Because it affects the last nucleotide of exon 2, its principal consequence is abnormal splicing rather than a simple missense substitution. The affected male died at 48 hours. (amategarcia2023anovelmutation pages 5-6, amategarcia2023anovelmutation pages 2-5)
• c.391G>A, p.Glu131Lys: de novo variant found by whole-genome sequencing in a female neonate with obstructive hypertrophic cardiomyopathy, lactic acidosis, progressive heart failure, and death by three months. (tariq2024casereportsevere pages 1-2)
• Previously summarized pathogenic alleles include nonsense/frameshift variants such as p.Trp85*, p.Arg88*, p.Tyr108*, and p.Arg134Serfs*3, particularly among symptomatic females. (amategarcia2023anovelmutation pages 8-9)

The 2023 report counted eight pathogenic NDUFB11 variants among 15 previously reported patients, with cardiomyopathy in approximately 67%. This statistic describes the reported NDUFB11 disease spectrum, not the proportion of all HC attributable to NDUFB11. (amategarcia2023anovelmutation pages 6-8)

Population allele frequencies were not available in the retrieved evidence. Given severe early-onset disease and ACMG classifications, causal alleles are expected to be absent or extremely rare in reference populations, but each variant requires direct gnomAD/ClinVar verification before database deposition. Variants are germline; no recurrent somatic mechanism is established.

Functional consequence

For c.338G>A, the normal 462-bp canonical transcript (NM_001135998; 153 amino acids) was lost, while a 492-bp alternative transcript retaining 30 additional bases increased. The longer RNA did not generate stable functional protein. NDUFB11 protein was undetectable in heart and severely reduced in skeletal muscle; skeletal-muscle complex-I activity was 22.7% of control. Respiratory supercomplex analysis showed reduced complex I within the respirasome and I+III₂ assemblies, with compensatory accumulation of III₂+IV and dimeric IV species. (amategarcia2023anovelmutation pages 6-8, amategarcia2023anovelmutation pages 5-6, amategarcia2023anovelmutation pages 2-5)

Direct abstract-level statement from the 2023 study: “the canonical ‘short’ transcript is required for the proper NDUFB11 protein synthesis, which is essential for optimal CI assembly and activity.” (amategarcia2023anovelmutation pages 6-8)

No validated modifier gene, recurrent chromosomal rearrangement, disease-specific DNA-methylation signature, or pathogenic somatic clone is established. X-inactivation is the best-supported epigenetic modifier.

5. Environmental information

There is no established role for smoking, diet, exercise, alcohol, pollution, radiation, occupational toxins, medication exposure, or infection in initiating HC. Acute illness may unmask mitochondrial energy failure or precipitate arrhythmia, but this is a physiologic stress response rather than a proven etiologic gene–environment interaction. No pathogen, zoonotic agent, vaccine relationship, or transmissible mechanism applies.

6. Mechanism and pathophysiology

Causal chain

Upstream germline variant → altered NDUFB11 transcript or protein → defective assembly/stability of mitochondrial respiratory-chain complex I → impaired NADH-to-ubiquinone electron transfer and oxidative phosphorylation → deficient ATP production, disturbed redox balance, and compensatory mitochondrial proliferation in energy-intensive cardiomyocytes → swollen/oncocytic “histiocytoid” cells, preferentially involving conduction-system-rich myocardial regions → abnormal impulse formation/conduction and myocardial dysfunction → ventricular tachyarrhythmia, heart failure, cardiac arrest, or sudden death. Patient heart and skeletal-muscle studies directly support the transcript-to-complex-I portion of this chain. (amategarcia2023anovelmutation pages 6-8, amategarcia2023anovelmutation pages 5-6, amategarcia2023anovelmutation pages 2-5)

Cells, anatomy, and ontology suggestions

• Cell types: working cardiomyocyte; cardiac conduction/Purkinje-like myocyte. Suggested CL terms: cardiac muscle cell and cardiac Purkinje cell; exact current identifiers should be ontology-validated.
• Processes: GO term suggestions—mitochondrial respiratory chain complex I assembly, mitochondrial electron transport, NADH to ubiquinone, oxidative phosphorylation, ATP metabolic process, mitochondrial organization, and cardiac muscle contraction.
• Compartments: GO suggestions—mitochondrion, mitochondrial inner membrane, respiratory-chain complex I, and mitochondrial respirasome.
• Downstream damage: energy failure, electrical instability, myocardial hypertrophy/remodeling, and terminal low-output/multiorgan failure. Chronic inflammation, autoimmunity, and primary fibrosis are not established initiating mechanisms.

Molecular profiling and advanced technologies

A historical whole-genome-expression study proposed candidate pathways, but no replicated diagnostic expression signature exists. The most informative recent profiling used RT-qPCR, Western blotting, blue-native PAGE, two-dimensional BN/SDS-PAGE, and enzyme assays in patient heart and muscle. (amategarcia2023anovelmutation pages 9-11)

No disease-specific single-cell RNA-seq, spatial transcriptomic atlas, proteomic cohort, metabolomic/lipidomic signature, CRISPR screen, or integrated multi-omics study was identified. Lactic acidosis is a nonspecific marker of respiratory-chain dysfunction, not an HC-specific metabolomic biomarker.

7. Anatomical structures affected

The primary organ is the heart, especially ventricular myocardium and endocardium, with frequent involvement of atrioventricular and sinoatrial nodal/conduction regions. Lesions are often multiple rather than lateralized. Suggested UBERON terms are heart, myocardium, endocardium, cardiac ventricle, interventricular septum, sinoatrial node, and atrioventricular node. (burke2016the2015who pages 2-3)

At tissue level, cardiac muscle and specialized conducting myocardium are affected. At subcellular level, the mitochondrial inner membrane and respiratory-chain complex I are central. Secondary organs may become involved through low cardiac output/multiorgan failure or as part of a syndromic NDUFB11 disorder; they are not necessarily sites of histiocytoid lesions.

8. Temporal development

HC is generally congenital or infantile. Most recognized patients present during the first year; severe NDUFB11 disease may manifest prenatally with hypertrophy/growth restriction or within hours after birth with lactic acidosis and heart failure. Nonetheless, asymptomatic childhood cases occur. (burke2016the2015who pages 2-3, adorisio2025mitochondrialcardiomyopathiesnavigating pages 3-4, tariq2024casereportsevere pages 1-2)

The course is highly variable:

• Hyperacute: neonatal metabolic decompensation, refractory heart failure, or fatal arrhythmia within hours or days.
• Episodic: recurrent ventricular tachycardia between periods of relative stability.
• Progressive: increasing hypertrophy, obstruction, systolic dysfunction, and heart failure.
• Occult: sudden death without a prior diagnosis.

There are no validated stages or remission criteria. The neonatal period and first year are the highest-risk windows; mortality is greatest among those diagnosed before one year. (adorisio2025mitochondrialcardiomyopathiesnavigating pages 3-4)

9. Inheritance and population

No population-based prevalence or incidence has been established. “Fewer than 150 reported cases” is a publication count, not prevalence. HC is therefore appropriately classified as ultra-rare. (burke2016the2015who pages 2-3)

NDUFB11-associated disease is X-linked, with variable penetrance and expressivity determined partly by variant class and X-inactivation. Males may have severe hemizygous neonatal disease; heterozygous females range from unaffected to lethal disease. De novo variants occur. Genetic anticipation, founder effects, consanguinity effects, carrier frequency, and germline mosaicism rates have not been established. (amategarcia2023anovelmutation pages 6-8, amategarcia2023anovelmutation pages 5-6, tariq2024casereportsevere pages 1-2)

No robust ethnic or geographic enrichment is known. Historical female predominance should not be converted into a precise sex ratio because of small samples, male prenatal/neonatal lethality, and case-selection bias.

10. Diagnostics

Clinical workflow

1. Recognize the phenotype: infant with unexplained ventricular ectopy/tachycardia, cardiac arrest, hypertrophic or noncompaction cardiomyopathy, or syndromic features.
2. Electrophysiology: 12-lead ECG, continuous telemetry, Holter/event monitoring, and electrophysiology study when ablation is contemplated.
3. Imaging: echocardiography for hypertrophy, obstruction, ventricular function, and noncompaction; cardiac MRI for anatomy, multifocal lesions, tissue characterization, and scar when feasible.
4. Metabolic evaluation: serum lactate, pyruvate and ratio, blood gas, glucose, creatine kinase, acylcarnitines, amino/organic acids, complete blood count for sideroblastic anemia, and broader mitochondrial assessment. Normal values do not exclude HC.
5. Genetics: rapid trio WGS or WES with copy-number and mitochondrial-genome analysis is preferred in critically ill infants. At minimum, panels must include NDUFB11 and relevant nuclear/mtDNA mitochondrial cardiomyopathy genes. A 2024 pathogenic NDUFB11 variant was missed by commercial cardiomyopathy panels and detected by WGS. (tariq2024casereportsevere pages 1-2)
6. Tissue studies: myocardial biopsy or explanted/autopsy heart can establish morphology. When available, electron microscopy, mitochondrial immunohistochemistry, respiratory-chain enzyme testing, RNA studies, and BN-PAGE can confirm mechanism. Skeletal muscle may show biochemical complex-I deficiency despite bland histology. (amategarcia2023anovelmutation pages 5-6)

Pathology

Expected findings include multifocal nodules or sheets of large polygonal cells with pale, foamy/eosinophilic granular cytoplasm, reduced contractile apparatus, and abundant abnormal mitochondria. Immunophenotyping supports myocardial/conduction-cell rather than macrophage origin. Definitive interpretation requires correlation with lesion distribution and ultrastructure because “histiocytoid” describes appearance, not lineage.

Differential diagnosis

Important alternatives are rhabdomyoma, fibroma, Purkinje-cell/conduction-system lesions, glycogen-storage cardiomyopathy, fatty or vacuolated myocardial change, myocarditis, mitochondrial cytopathy without histiocytoid morphology, sarcomeric HCM, left-ventricular noncompaction, arrhythmogenic cardiomyopathy, channelopathy/long-QT syndrome, and tachycardia-induced cardiomyopathy. Distinguishing features include multifocal mitochondria-rich histiocytoid myocytes, conduction-system distribution, mitochondrial biochemical/genetic findings, and absence of a conventional neoplastic architecture.

There are no universally accepted disease-specific clinical diagnostic criteria. Prenatal or cascade testing is possible only after a familial pathogenic variant has been established. HC is not part of routine newborn screening.

11. Outcome and prognosis

The prognosis is guarded, especially with neonatal or first-year presentation, complex-I deficiency, persistent ventricular arrhythmia, or progressive ventricular dysfunction. Recent molecularly solved severe cases ended in death at 48 hours and three months, respectively. (amategarcia2023anovelmutation pages 2-5, tariq2024casereportsevere pages 1-2)

No reliable 5- or 10-year survival rate, life-expectancy estimate, disability-adjusted burden, or validated prognostic model exists. Major complications are recurrent ventricular tachycardia, torsades/ventricular fibrillation, sudden death, heart failure, thromboembolic or device complications, and multiorgan failure. Earlier diagnosis, localized resectable disease, rhythm control, and access to mechanical support/transplant may improve individual outcomes, but comparative effectiveness has not been established.

12. Treatment and current implementation

No medication, gene therapy, RNA therapy, or mitochondrial therapy is approved specifically for HC. Management is individualized in a pediatric electrophysiology, heart-failure, mitochondrial-genetics, and cardiac-surgery center.

• Acute arrhythmia care: resuscitation, cardioversion/defibrillation, correction of electrolyte and acid–base disturbances, and intravenous antiarrhythmics according to rhythm and pediatric protocols.
• Chronic rhythm control: beta-blockers, amiodarone, sodium-channel blockers, or combinations have been used. A 2023 case report proposed high-dose carvedilol, but a single case cannot establish efficacy. In the 2024 NDUFB11 female case, beta-blockade did not prevent progressive failure. (tariq2024casereportsevere pages 1-2)
• Catheter ablation: may control a dominant premature-ventricular-complex or ventricular-tachycardia focus, including reported infant torsades triggers; multifocal myocardial disease limits durability.
• Surgical excision: considered when a discrete arrhythmogenic lesion can be safely localized and removed.
• Device therapy: pacemaker or implantable cardioverter-defibrillator decisions are individualized; small infant size and rapidly progressive disease complicate implantation.
• Heart-failure support: diuretics, afterload reduction, inotropes, ventilation, and nutritional/metabolic support as clinically indicated.
• Advanced support: ECMO or biventricular assist devices have been used as rescue/bridge strategies; orthotopic heart transplantation has been reported.
• Mitochondrial supplements: coenzyme Q10, riboflavin, thiamine, or related “mitochondrial cocktails” may be considered for broader mitochondrial disease but have no demonstrated HC-specific response rate.

Suggested NCIT intervention terms include Antiarrhythmic Therapy, Beta-Blocker Therapy, Electrical Cardioversion, Catheter Ablation, Surgical Resection, Implantable Cardioverter Defibrillator, Extracorporeal Membrane Oxygenation, Ventricular Assist Device, and Heart Transplantation. No disease-specific interventional ClinicalTrials.gov study was identified in the tool search.

13. Prevention

Primary prevention through lifestyle or immunization is not applicable. For a family with a pathogenic variant, prevention and early detection consist of genetic counseling, cascade testing, reproductive options such as prenatal or preimplantation genetic testing, and fetal echocardiography/rhythm assessment. Because X-inactivation makes female phenotype prediction unreliable, genotype alone cannot precisely predict severity.

Secondary prevention includes early ECG/echo surveillance of at-risk relatives and rapid evaluation of unexplained infantile arrhythmia. Tertiary prevention focuses on suppressing recurrent arrhythmia, preventing heart-failure decompensation, providing emergency-action planning, and considering ablation/device/advanced-heart-failure therapy before irreversible deterioration. There is no population screening program or prophylactic medication supported by disease-specific trials.

14. Other species and natural disease

A naturally occurring analogous lesion—Purkinje-fiber dysplasia/histiocytoid cardiomyopathy with ventricular noncompaction—has been described in a Savannah kitten. This supports comparative conservation of specialized conduction cardiomyocytes and mitochondrial pathology, but one veterinary case does not establish breed predisposition or a homologous NDUFB11 cause. Suggested taxonomy: Felis catus, NCBI Taxonomy 9685. No zoonotic or cross-species transmission exists.

15. Model organisms

No validated engineered animal model was identified that reproduces the complete human combination of histiocytoid myocardial lesions, infantile malignant arrhythmia, sex bias, and NDUFB11-associated complex-I deficiency. The naturally affected feline case is a comparative-pathology model rather than a standardized experimental system.

Mechanistic work has instead used patient heart/skeletal muscle and NDUFB11 knockdown cell systems. The 2023 human-tissue study combined transcript analysis, respiratory-chain enzyme measurement, immunoblotting, and supercomplex analysis; this directly models biochemical disease but cannot reproduce whole-heart electrophysiology. (amategarcia2023anovelmutation pages 5-6, amategarcia2023anovelmutation pages 9-11)

Useful future systems include conditional cardiomyocyte- or conduction-cell-specific Ndufb11 mouse models, zebrafish rhythm models, CRISPR-engineered human iPSC cardiomyocytes, and cardiac/conduction-system organoids. Essential readouts would be complex-I assembly, oxygen consumption, ATP/redox state, mitochondrial ultrastructure, action potentials, triggered activity, conduction velocity, and arrhythmia susceptibility.

Recent developments, 2023–2024

• January 2023: Amate-García and colleagues functionally characterized NDUFB11 c.338G>A in affected human tissues. Their work showed that a nominal “missense” change was actually splice-disrupting, eliminated the functional short transcript, altered respiratory supercomplexes, and reduced skeletal-muscle complex-I activity to 22.7% of control. DOI: https://doi.org/10.3390/ijms24021743. (amategarcia2023anovelmutation pages 6-8, amategarcia2023anovelmutation pages 2-5)
• November 2023: A case report described high-dose carvedilol as a potential antiarrhythmic strategy; this remains anecdotal and should not be generalized without comparative data. DOI: https://doi.org/10.1093/ehjcr/ytad588.
• July 2024: Tariq and colleagues reported the first female neonate with severe obstructive HCM attributed to de novo NDUFB11 c.391G>A (p.Glu131Lys). Rapid WGS succeeded where commercial cardiomyopathy panels did not; the infant died by three months despite beta-blockade. DOI: https://doi.org/10.1093/ehjcr/ytae377. (tariq2024casereportsevere pages 1-2, tariq2024casereportsevere pages 2-3)

These developments reinforce two expert conclusions: NDUFB11 disease is broader than classical histiocytoid morphology, and broad rapid genomic testing plus functional RNA/protein studies may be necessary to establish pathogenicity.

Evidence-quality assessment and priority gaps

Evidence is strongest for the infantile arrhythmic phenotype, conduction-system-like mitochondrial pathology, and NDUFB11/complex-I mechanism. It is weakest for epidemiologic rates, penetrance, treatment effectiveness, long-term quality of life, and genotype-specific prognosis. There are no prospective natural-history studies, standardized criteria, validated circulating biomarkers, disease-specific trials, or replicated advanced-omics datasets. Reported-case totals and phenotype percentages are especially vulnerable to publication and survivor bias. Accordingly, treatment claims should remain labeled case-report/series evidence, while NDUFB11 functional findings can be labeled human tissue molecular evidence.

Key source links and dates

1. Burke A, Tavora F. The 2015 WHO Classification of Tumors of the Heart and Pericardium. Published April 2016. https://doi.org/10.1016/j.jtho.2015.11.009. (burke2016the2015who pages 2-3)
2. Amate-García G, et al. A Novel Mutation Associated with Neonatal Lethal Cardiomyopathy Leads to an Alternative Transcript Expression in the X-Linked Complex I NDUFB11 Gene. Published January 2023. https://doi.org/10.3390/ijms24021743. (amategarcia2023anovelmutation pages 6-8, amategarcia2023anovelmutation pages 5-6)
3. Tariq J, et al. Severe hypertrophic cardiomyopathy in a female neonate caused by de novo variant in NDUFB11. Published July 2024. https://doi.org/10.1093/ehjcr/ytae377. (tariq2024casereportsevere pages 1-2)
4. Open Targets Platform, disease–target record for MONDO:0010771 and NDUFB11, accessed through the current tool query. (OpenTargets Search: histiocytoid cardiomyopathy-NDUFB11)
5. Adorisio R, et al. Mitochondrial cardiomyopathies: navigating through different clinical and management pictures between adult and paediatric forms. Published July 2025; used only as a current contextual review where 2023–2024 HC-specific evidence was sparse. https://doi.org/10.3389/fcvm.2025.1621096. (adorisio2025mitochondrialcardiomyopathiesnavigating pages 3-4)

References

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8. (amategarcia2023anovelmutation pages 2-5): Guillermo Amate-García, María Juliana Ballesta-Martínez, Pablo Serrano-Lorenzo, Rocío Garrido-Moraga, Adrián González-Quintana, Alberto Blázquez, Juan C. Rubio, Inés García-Consuegra, Joaquín Arenas, Cristina Ugalde, María Morán, Encarnación Guillén-Navarro, and Miguel A. Martín. A novel mutation associated with neonatal lethal cardiomyopathy leads to an alternative transcript expression in the x-linked complex i ndufb11 gene. International Journal of Molecular Sciences, 24:1743, Jan 2023. URL: https://doi.org/10.3390/ijms24021743, doi:10.3390/ijms24021743. This article has 16 citations.

9. (amategarcia2023anovelmutation pages 8-9): Guillermo Amate-García, María Juliana Ballesta-Martínez, Pablo Serrano-Lorenzo, Rocío Garrido-Moraga, Adrián González-Quintana, Alberto Blázquez, Juan C. Rubio, Inés García-Consuegra, Joaquín Arenas, Cristina Ugalde, María Morán, Encarnación Guillén-Navarro, and Miguel A. Martín. A novel mutation associated with neonatal lethal cardiomyopathy leads to an alternative transcript expression in the x-linked complex i ndufb11 gene. International Journal of Molecular Sciences, 24:1743, Jan 2023. URL: https://doi.org/10.3390/ijms24021743, doi:10.3390/ijms24021743. This article has 16 citations.

10. (amategarcia2023anovelmutation pages 1-2): Guillermo Amate-García, María Juliana Ballesta-Martínez, Pablo Serrano-Lorenzo, Rocío Garrido-Moraga, Adrián González-Quintana, Alberto Blázquez, Juan C. Rubio, Inés García-Consuegra, Joaquín Arenas, Cristina Ugalde, María Morán, Encarnación Guillén-Navarro, and Miguel A. Martín. A novel mutation associated with neonatal lethal cardiomyopathy leads to an alternative transcript expression in the x-linked complex i ndufb11 gene. International Journal of Molecular Sciences, 24:1743, Jan 2023. URL: https://doi.org/10.3390/ijms24021743, doi:10.3390/ijms24021743. This article has 16 citations.

11. (amategarcia2023anovelmutation pages 9-11): Guillermo Amate-García, María Juliana Ballesta-Martínez, Pablo Serrano-Lorenzo, Rocío Garrido-Moraga, Adrián González-Quintana, Alberto Blázquez, Juan C. Rubio, Inés García-Consuegra, Joaquín Arenas, Cristina Ugalde, María Morán, Encarnación Guillén-Navarro, and Miguel A. Martín. A novel mutation associated with neonatal lethal cardiomyopathy leads to an alternative transcript expression in the x-linked complex i ndufb11 gene. International Journal of Molecular Sciences, 24:1743, Jan 2023. URL: https://doi.org/10.3390/ijms24021743, doi:10.3390/ijms24021743. This article has 16 citations.

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