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Classifications

Harrison's Chapter

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Inheritance

1

Autosomal dominant inheritance HP:0000006

Heterozygous PHIP variants act dominantly through haploinsufficiency. Most probands carry de novo alleles, but a consistent minority are inherited from a mildly affected parent, and multigenerational segregation has been documented - so a normal-appearing parent should not be assumed to be a non-carrier without testing. Penetrance for the neurodevelopmental core appears high; penetrance for obesity specifically is incomplete.

Autosomal dominant inheritance Expressivity: VARIABLE

Show evidence (4 references)

PMID:37961033 SUPPORT Human Clinical

"Variants were de novo in 61.7%, unknown inheritance in 29.8%, and inherited in 8.5%."

Quantifies the de novo versus inherited split in the largest reported cohort.

PMID:36726590 SUPPORT Human Clinical

"Follow-up investigations (e.g. Sanger sequencing, qPCR or Fluorescence-in-situ-Hybridization) and segregation analysis showed either de novo occurrence or inheritance from an also (mildly) affected parent."

Documents both de novo origin and transmission from a mildly affected parent in the same European cohort.

PMID:36726590 SUPPORT Human Clinical

"The fact that some variants were inherited from a mildly affected parent further illustrates the variability of the associated phenotype"

Directly supports the VARIABLE expressivity assignment.

+ 1 more reference

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Mechanistic Hypotheses

3

Trivalent Chromatin Reading and CRL4 Recruitment Failure Branch

chromatin_reader_crl4_recruitment CANONICAL

Evidence balance 1 support

The canonical molecular lesion is loss of PHIP's activity as a multivalent chromatin reader. PHIP engages the nucleosome through three coordinated reader surfaces - a Tudor domain reading H3K4 methylation, BD1 reading H3K14ac, and BD2 reading H4K12ac - and it is this chromatin engagement that allows PHIP to act as the substrate receptor recruiting the CRL4 ubiquitin ligase to chromatin. Disease-associated PHIP variants map into each reader domain and into the linker between them, and are predicted to disrupt chromatin binding. This is the branch that makes CHUJANS a chromatinopathy rather than a generic NDD, and it is corroborated at the patient level by the disorder's DNA methylation episignature and by that signature's overlap with the PHF6 and DDB1 disorders.

Pathograph links

PHIP Haploinsufficiency -> Impaired Trivalent Nucleosome Reading by the PHIP Tudor-Bromodomain Module DIRECT

Impaired Trivalent Nucleosome Reading by the PHIP Tudor-Bromodomain Module -> Failure of CRL4 Substrate-Receptor Recruitment to Chromatin DIRECT

Failure of CRL4 Substrate-Receptor Recruitment to Chromatin -> Chung-Jansen DNA Methylation Episignature INDIRECT UNKNOWN INTERMEDIATES

Failure of CRL4 Substrate-Receptor Recruitment to Chromatin -> Disrupted Neurodevelopmental Gene Expression Program INDIRECT UNKNOWN INTERMEDIATES

Show evidence (1 reference)

PMID:34819353 SUPPORT In Vitro

"PHIP binds to chromatin through a trivalent reader domain consisting of a H3K4-methyl binding Tudor domain and two bromodomains (BD1 and BD2)."

Defines the trivalent reader architecture that this hypothesis branch is built on.

POMC Repression / Central Melanocortin Branch

pomc_melanocortin_repression EMERGING

Evidence balance 1 support

The obesity arm has its own, mechanistically distinct and comparatively well-developed model: nuclear PHIP directly enhances transcription of POMC, the precursor of the anorexigenic melanocortin peptides, and obesity-associated PHIP variants repress POMC transcription - linking PHIP dosage to central leptin-melanocortin satiety signaling. The status is EMERGING rather than CANONICAL because the demonstration is cell-based rather than in human hypothalamic POMC neurons, and because obesity is not fully penetrant in CHUJANS. This branch is not a competitor to the chromatin-reader branch; it is plausibly a tissue-specific readout of the same transcriptional-coactivator deficit, but that connection has not been shown directly.

Pathograph links

PHIP Haploinsufficiency -> Repressed POMC Transcription DIRECT

Repressed POMC Transcription -> Impaired Central Melanocortin Satiety Signaling DIRECT

Impaired Central Melanocortin Satiety Signaling -> Obesity and Overweight INDIRECT UNKNOWN INTERMEDIATES

Show evidence (1 reference)

PMID:32492392 SUPPORT In Vitro

"In cells, we found that nuclear PHIP (pleckstrin homology domain interacting protein) directly enhances transcription of pro-opiomelanocortin (POMC), a neuropeptide that suppresses appetite. Obesity-associated PHIP variants repressed POMC transcription."

The primary functional result underpinning this branch, and the explicit basis for its IN_VITRO evidence tag.

Replication Fork Protection / Genome Integrity Branch

replication_stress_genome_integrity EMERGING

Evidence balance 1 support

Full-length PHIP is also DCAF14, a replication stress response protein. Two CHUJANS missense variants in different functional elements (the WD40 repeat domain and the pleckstrin-homology-binding region) both cause defective replication fork progression under replication stress and fail to complete DNA replication after genotoxic insult. Whether this replication-associated genome instability contributes to the clinical phenotype - as opposed to being a parallel consequence of the same protein loss - is unresolved; no CHUJANS-specific cancer predisposition or chromosome-instability clinical phenotype has been established.

Pathograph links

PHIP Haploinsufficiency -> Replication Fork Destabilization Under Replication Stress DIRECT

Show evidence (1 reference)

PMID:35863899 SUPPORT In Vitro

"Using DNA fiber assays, we reveal that cells expressing either variant exhibit defective replication fork progression in conditions of replication stress."

Establishes the replication-stress defect for patient-derived CHUJANS alleles.

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Discussions and Knowledge Gaps

4

Does the demonstration that nuclear PHIP enhances POMC transcription, and that disease variants repress it, hold in human hypothalamic POMC neurons - the cells where the mechanism must operate for it to explain the obesity phenotype?

HUMAN MODEL MISMATCH OPEN chujans_pomc_mechanism_cell_context

Attached to

pathophysiology#Repressed POMC Transcription pathophysiology#Impaired Central Melanocortin Satiety Signaling

The POMC branch is the best-developed mechanistic account of any CHUJANS feature, but it rests on cell-based reporter and localization experiments rather than on human hypothalamic neurons, and the clinical phenotype it purports to explain is not fully penetrant - roughly 44% of individuals in the largest cohort are neither obese nor overweight. Two failure modes are therefore live: the effect could be real but quantitatively insufficient on its own, requiring modifiers to produce obesity; or it could be a property of the assay context. Either way the inference from a transfected-cell reporter to arcuate POMC neuron biology is currently unbridged, and the entry's mechanism_confidence values for this arm (PROVISIONAL, not ESTABLISHED) reflect that.

Proposed experiments

PHIP allelic series in human iPSC-derived hypothalamic POMC neurons

isogenic allelic-series loss-of-function experiment

exp_chujans_ipsc_hypothalamic_pomc

In an isogenic human iPSC background, build a PHIP allelic series (heterozygous null, plus heterozygous patient truncating and missense alleles) and differentiate to arcuate-like hypothalamic cultures containing POMC neurons. Read out POMC transcript and peptide levels, leptin responsiveness, PHIP occupancy at the POMC locus, and the local chromatin marks PHIP reads (H3K4me3, H3K14ac, H4K12ac). This tests, at human-matched zygosity and in the correct cell type, whether the reporter finding reproduces and whether it is chromatin-reading-dependent.

Which genes and regulatory elements lose PHIP-dependent chromatin reading and CRL4 recruitment in the developing human brain, and how does that produce the specific CHUJANS neurodevelopmental and behavioral phenotype?

KNOWLEDGE GAP OPEN chujans_chromatin_reader_to_neurodevelopment_gap

Attached to

pathophysiology#Failure of CRL4 Substrate-Receptor Recruitment to Chromatin pathophysiology#Disrupted Neurodevelopmental Gene Expression Program

The molecular top of the pathograph is unusually well resolved for a chromatinopathy - the reader domains, their histone marks, the CRL4 recruitment step, and a patient-level methylation episignature are all established - and the clinical bottom is well characterized across three cohorts. The middle is empty. No CHUJANS-specific patient neuron, brain organoid, or brain transcriptomic dataset exists, so no mis-regulated target gene has been identified, and the episignature's differentially methylated loci have not been connected to neurodevelopmental effector genes. This is why the neurodevelopmental node in this entry is tagged HYPOTHETICAL despite the phenotype itself being certain: the uncertainty is about the route, not the destination.

Proposed experiments

PHIP and CRL4 chromatin occupancy plus transcriptome in PHIP-haploinsufficient human neurons

chromatin occupancy and transcriptome profiling

exp_chujans_chip_and_transcriptome_neurons

Map PHIP and CUL4/DDB1 occupancy genome-wide (CUT&RUN or ChIP-seq) in wild-type versus PHIP-haploinsufficient human iPSC-derived cortical neurons and progenitors, alongside RNA-seq, ATAC-seq, and profiling of H3K4me3, H3K14ac, and H4K12ac. Intersect sites of lost PHIP/CRL4 occupancy with differentially expressed genes and with the differentially methylated loci that define the blood episignature, to identify candidate effector genes bridging the reader defect and the neurodevelopmental phenotype.

Does the replication-fork protection defect caused by CHUJANS PHIP/DCAF14 variants produce any measurable clinical consequence - genome instability, cancer predisposition, or a contribution to the neurodevelopmental phenotype - in affected individuals?

KNOWLEDGE GAP OPEN chujans_replication_instability_clinical_consequence

Attached to

pathophysiology#Replication Fork Destabilization Under Replication Stress

Two patient missense alleles demonstrably impair replication fork progression and stalled-fork protection, and the authors explicitly predict replication-associated genome instability in the syndrome. But that prediction has never been tested in patients: no CHUJANS cohort has been screened for chromosomal instability, no cancer incidence data exist, and the tested alleles are two missense variants rather than the truncating alleles that dominate the reported spectrum. PHIP expression alterations are separately linked to cancer, which makes the question non-trivial rather than academic. Until it is answered, this arm cannot be given a clinical downstream and no surveillance recommendation can be justified from it.

Proposed experiments

Genome-instability and neoplasia assessment in a CHUJANS cohort

patient-derived cell genome instability assay

exp_chujans_patient_genome_instability

In patient-derived lymphoblastoid or fibroblast lines spanning truncating, deletion, and missense PHIP alleles, measure baseline and induced chromosomal instability (micronucleus formation, chromosome aberrations, replication-stress markers, DNA fiber fork progression) against controls. In parallel, assemble cancer and neoplasia incidence from an international CHUJANS registry cohort (for example via Simons Searchlight) to determine whether the in vitro defect has any epidemiological correlate.

What is the true population prevalence of Chung-Jansen syndrome, and how much of the apparent rarity is underdiagnosis of mildly affected individuals?

KNOWLEDGE GAP OPEN chujans_population_prevalence_unknown

Attached to

pathophysiology#PHIP Haploinsufficiency

No validated prevalence or incidence estimate exists; only cumulative published case counts on the order of one hundred individuals. Two features make the published count a likely underestimate rather than a reasonable proxy: alleles are repeatedly inherited from parents whose learning, behavioral, or weight phenotype was recognized only after their child was diagnosed, and the cardinal features (mild learning difficulty, ADHD, anxiety, overweight) are individually common and unlikely to trigger genetic testing in isolation. Reliable denominators would come from unbiased population-scale sequencing rather than from further clinically ascertained cohorts.

Proposed experiments

Population-scale PHIP loss-of-function ascertainment with reverse phenotyping

genotype-first population cohort study

exp_chujans_biobank_prevalence

Query large unselected biobank and population sequencing resources for high-confidence PHIP loss-of-function alleles, then reverse-phenotype carriers for cognitive, behavioral, anthropometric, and urorenal traits. This yields both a genotype-first prevalence estimate and a penetrance estimate for each cardinal feature that is not distorted by clinical ascertainment.

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Pathophysiology

10

Heterozygous PHIP Loss-of-Function Variation

The initiating lesion is a heterozygous, usually germline PHIP variant at 6q14.1. The allelic spectrum is broad and shows no clustering hotspot: nonsense and frameshift truncations, splice variants, missense substitutions, and intragenic, whole-gene, or contiguous deletions extending into adjacent genomic regions are all reported. Larger deletions can produce a blended phenotype because neighbouring genes are co-deleted.

PHIP hgnc:15673

Downstream

PHIP Haploinsufficiency

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"including, truncating variants, missense substitutions, splice variants and large deletions encompassing portions of the gene or the entire gene as well as adjacent genomic regions"

Enumerates the reported allelic classes, including structural alleles.

PMID:31167805 SUPPORT Human Clinical

"The mutation spectrum is diverse, and there is no clustering of mutations across the protein."

Establishes the absence of a mutational hotspot, which is why the entry models dosage loss rather than a domain-restricted allele class.

PHIP Haploinsufficiency

Loss of one functional PHIP allele halves the dose of the chromatin-reader / CRL4 substrate receptor. Haploinsufficiency, not a gain of function, is the accepted mechanism, and the genotype-phenotype analysis that delineated the syndrome assigned the causal isoform specifically to PHIP/DCAF14 rather than to the alternative NDRP product of the same locus. The same locus additionally encodes a protein implicated in IGF-1 signalling, so PHIP dosage loss is not confined to the nuclear chromatin arm.

POMC Repression / Central Melanocortin Branch Replication Fork Protection / Genome Integrity Branch Trivalent Chromatin Reading and CRL4 Recruitment Failure Branch

PHIP hgnc:15673

Downstream

Impaired Trivalent Nucleosome Reading by the PHIP Tudor-Bromodomain Module

Repressed POMC Transcription

Replication Fork Destabilization Under Replication Stress

Disrupted PHIP-Dependent Kidney and Urinary Tract Development

Show evidence (3 references)

PMID:29209020 SUPPORT Human Clinical

"Detailed genotype-phenotype analysis points towards haploinsufficiency of PHIP/DCAF14, and not NDRP, as the underlying cause of the phenotype."

Assigns haploinsufficiency, and specifically the PHIP/DCAF14 isoform, as the disease mechanism.

PMID:39156152 SUPPORT Human Clinical

"The neurodevelopmental disorder Chung-Jansen syndrome (CHUJANS) is caused by haploinsufficiency of Pleckstrin homology domain-interacting protein (PHIP)"

Independent restatement of haploinsufficiency as the established mechanism.

PMID:42355777 PARTIAL Human Clinical

"which encodes a protein involved in neurodevelopmental processes and IGF-1 signalling"

Notes the second, non-chromatin (IGF-1 signalling) function attributed to the PHIP products; PARTIAL because that arm is not developed into a curated pathophysiology node for lack of CHUJANS-specific mechanistic evidence.

Impaired Trivalent Nucleosome Reading by the PHIP Tudor-Bromodomain Module

PHIP is a BRD/BRWD-family multivalent chromatin reader. Semisynthetic nucleosomes with defined histone modifications show that its three reader surfaces are non-redundant and combinatorial: a Tudor domain reads H3K4 methylation, the first bromodomain (BD1) reads acetylated H3K14, and the second bromodomain (BD2) reads acetylated H4K12. Because CHUJANS variants occur in each of these domains and in the linker that positions them relative to one another, the primary molecular defect is failure to engage appropriately marked nucleosomes - a reading defect, not a writing or erasing defect. Note the epistemic split within this node: the reader architecture and its mark specificities are measured biochemistry, whereas the impairment of that reading by patient alleles is inferred from variant location and is described by the source as likely rather than demonstrated - hence PROVISIONAL rather than ESTABLISHED confidence.

Trivalent Chromatin Reading and CRL4 Recruitment Failure Branch

H3K4-methyl binding Tudor domain reader activity GO:0140002 ↓ DECREASED PHIP bromodomain 1 (BD1) reading of H3K14ac GO:0140015 ↓ DECREASED PHIP bromodomain 2 (BD2) reading of H4K12ac GO:0140011 ↓ DECREASED chromatin binding GO:0003682 ↓ DECREASED

Downstream

Failure of CRL4 Substrate-Receptor Recruitment to Chromatin

Show evidence (2 references)

PMID:34819353 SUPPORT In Vitro

"Using semisynthetic nucleosomes with defined histone post-translational modifications, we characterize PHIPs BD1 and BD2 as respective readers of H3K14ac and H4K12ac, and identify human disease-associated mutations in each domain and the intervening linker region that likely disrupt chromatin binding."

Assigns the specific acetyl-lysine marks read by each bromodomain and localizes disease variants to those reader modules.

PMID:34819353 SUPPORT Other

"Mutations in the PHIP/BRWD2 chromatin regulator cause the human neurodevelopmental disorder Chung-Jansen syndrome"

Frames PHIP explicitly as a chromatin regulator and ties it to this disorder.

Failure of CRL4 Substrate-Receptor Recruitment to Chromatin

PHIP (as DCAF14) is one of several substrate receptors of the CUL4-DDB1 (CRL4) E3 ubiquitin ligase, and it is specifically the chromatin-associated one - PHIP is required for CRL4 to be recruited to chromatin at all. Reduced PHIP dose therefore removes chromatin-localized CRL4 activity, with consequences for ubiquitin-dependent turnover of chromatin substrates and for chromatin-templated transcription. The clinical corroboration of this node is the phenotypic overlap of PHIP loss with CUL4B deficiency, which likewise causes intellectual disability with central obesity and dysmorphism.

Trivalent Chromatin Reading and CRL4 Recruitment Failure Branch

chromatin-associated protein ubiquitination GO:0016567 ↓ DECREASED regulation of transcription by RNA polymerase II GO:0006357 ⚠ ABNORMAL

CRL4 (CUL4-DDB1) E3 ubiquitin ligase complex GO:0080008

Downstream

Chung-Jansen DNA Methylation Episignature

Disrupted Neurodevelopmental Gene Expression Program

Show evidence (2 references)

PMID:35863899 SUPPORT Other

"CJS is associated with heterozygous variants in PHIP (Pleckstrin-Homology Interacting Protein), a gene that encodes one of several substrate receptors for Cullin4-RING (CRL4) E3 ubiquitin ligase complex."

Establishes PHIP's identity as a CRL4 substrate receptor.

PMID:27900362 SUPPORT Human Clinical

"The overlapping phenotype associated with CUL4B deficiency suggests that PHIP mutations cause disease through disruption of the ubiquitin ligase pathway."

Human-genetic corroboration: another component of the same ligase, when lost, produces an overlapping ID-plus-central-obesity phenotype.

Chung-Jansen DNA Methylation Episignature

Affected individuals carry a specific and sensitive genome-wide DNA methylation signature detectable on Infinium Methylation EPIC arrays. Two things make this more than a diagnostic convenience. First, it is direct patient-level (not cell-line) evidence that PHIP haploinsufficiency perturbs the epigenome, which is the prediction of the chromatin-reader model. Second, the CHUJANS signature partially overlaps those of White-Kernohan syndrome (DDB1 - the very CRL4 adaptor that PHIP docks onto) and Borjeson-Forssman-Lehmann syndrome (PHF6, another chromatin-associated NDD protein), so the shared episignature independently recovers the functional relationship rather than merely the clinical resemblance.

Show evidence (2 references)

PMID:38787418 SUPPORT Human Clinical

"We assessed the DNAm profiles of affected individuals with pathogenic and likely pathogenic PHIP variants with Infinium Methylation EPIC arrays and report a specific and sensitive DNAm episignature biomarker for Chung-Jansen syndrome."

Establishes the existence and diagnostic character of the episignature in patients.

PMID:38787418 SUPPORT Human Clinical

"we observed similarities between the methylation profile of Chung-Jansen syndrome and that of functionally related and clinically partially overlapping genetic disorders, White-Kernohan syndrome (caused by variants in DDB1 gene) and Börjeson-Forssman-Lehmann syndrome (caused by variants in PHF6 gene)"

The cross-disorder overlap with DDB1 and PHF6 disorders is the evidence that the signature reflects shared chromatin-machinery pathophysiology.

Replication Fork Destabilization Under Replication Stress

A mechanistically separate consequence of PHIP/DCAF14 loss. Two CHUJANS missense variants located in different functional elements of DCAF14 - one in the WD40 repeat domain, one in the pleckstrin-homology-binding region - both cause defective replication fork progression under replication stress and both fail to complete DNA replication after genotoxic exposure, implicating DCAF14 in the protection of stalled forks. The authors accordingly predict replication-associated genome instability in CHUJANS. Note that this is a prediction: no clinical instability phenotype (cancer predisposition, chromosome breakage) has been demonstrated in CHUJANS patients, so this node is modelled as a cellular defect without a curated clinical consequence.

replication fork processing GO:0031297 ⚠ ABNORMAL

Show evidence (3 references)

PMID:35863899 SUPPORT In Vitro

"The variants p.D488V and p.E963G occur in different functional elements of DCAF14- WD40 repeat domain and pleckstrin homology-binding region (PBR), respectively."

Identifies the two patient alleles tested and their domain locations.

PMID:35863899 SUPPORT In Vitro

"Furthermore, unlike wild type DCAF14, both variants fail to accomplish DNA replication after exposure to genotoxic stress indicating a critical role of DCAF14 in protecting stalled replication forks."

Demonstrates the stalled-fork protection defect for both patient variants.

PMID:35863899 PARTIAL In Vitro

"Thus, we have identified replication defects associated with CJS variants and predict replication-associated genome instability with CJS syndrome."

The genome-instability consequence in patients is explicitly framed by the authors as a prediction, which is why this node is HYPOTHETICAL and has no curated clinical downstream.

Repressed POMC Transcription

PHIP has nuclear and cytoplasmic pools, and it is the nuclear pool that acts on POMC. Nuclear PHIP directly enhances transcription of pro-opiomelanocortin, the precursor from which the anorexigenic melanocortin peptides are cleaved, and obesity-associated PHIP variants repress that transcription. The physiological setting is the hypothalamic arcuate POMC neuron, the first-order anorexigenic node of the leptin-melanocortin pathway; the experimental demonstration, however, was in cells rather than in human hypothalamic neurons, which is the principal limitation of this arm.

POMC Repression / Central Melanocortin Branch

hypothalamic POMC (anorexigenic) neuron CL:4042033

positive regulation of POMC transcription by RNA polymerase II GO:0045944 ↓ DECREASED

arcuate nucleus of the hypothalamus UBERON:0001932

Downstream

Impaired Central Melanocortin Satiety Signaling

Show evidence (2 references)

PMID:32492392 SUPPORT In Vitro

"In cells, we found that nuclear PHIP (pleckstrin homology domain interacting protein) directly enhances transcription of pro-opiomelanocortin (POMC), a neuropeptide that suppresses appetite."

Establishes nuclear PHIP as a direct positive regulator of POMC transcription and names the anorexigenic function of the product.

PMID:34773373 PARTIAL Computational

"Protein-protein interactions indicate involvement of POMC and related proteins with potential contribution to obesity, congenital, neuromuscular, and lipid disorders"

Independent in silico interaction analysis recovers the PHIP-POMC relationship; PARTIAL because it is predictive rather than experimental.

Impaired Central Melanocortin Satiety Signaling

Reduced POMC-derived melanocortin tone weakens the central satiety signal downstream of leptin, biasing energy balance toward positive. Clinically this manifests as overweight or obesity that is not usually present at birth but emerges between early childhood and puberty and becomes more prevalent with age - so a normal weight in a young child does not exclude the diagnosis or predict a normal adult weight.

POMC Repression / Central Melanocortin Branch

regulation of feeding behavior GO:0060259 ⚠ ABNORMAL energy homeostasis GO:0097009 ⚠ ABNORMAL

hypothalamus UBERON:0001898

Downstream

Obesity and Overweight

Show evidence (1 reference)

PMID:37961033 PARTIAL Human Clinical

"The percentage of obese individuals was greater in the older age group (>12 years old) and evolves over time."

Documents the age-dependent emergence of the weight phenotype at the clinical level; PARTIAL because it evidences the downstream weight outcome rather than melanocortin signaling itself.

Disrupted Neurodevelopmental Gene Expression Program

The route from chromatin-reading failure to the neurodevelopmental phenotype is the least resolved segment of the CHUJANS pathograph. PHIP's isoforms are implicated in neurodevelopmental processes including neuronal differentiation, and the clinical output (global developmental delay, learning disability or intellectual disability, speech delay, hypotonia, and a behavioral/psychiatric profile) is highly consistent across cohorts. What is missing is any CHUJANS-specific patient-neuron, organoid, or brain transcriptomic dataset identifying the mis-regulated target genes, so the node is curated as a named but mechanistically unresolved intermediate rather than as an established pathway.

neuron CL:0000540

nervous system development GO:0007399 ⚠ ABNORMAL neuron differentiation GO:0030182 ⚠ ABNORMAL

brain UBERON:0000955

Downstream

Global Developmental Delay

Intellectual Disability

Behavioral and Psychiatric Problems

Hypotonia

Craniofacial Dysmorphism

Show evidence (1 reference)

PMID:29209020 PARTIAL Human Clinical

"PHIP encodes two protein-isoforms, PHIP/DCAF14 and NDRP, each involved in neurodevelopmental processes, including E3 ubiquitination and neuronal differentiation"

Attributes neurodevelopmental roles including neuronal differentiation to the PHIP products; PARTIAL because the specific dysregulated program is unknown.

Disrupted PHIP-Dependent Kidney and Urinary Tract Development

A distinct developmental arm outside the CNS. Prenatal expression studies in murine and human renal tissue support a role for PHIP in normal kidney and urinary tract development, and systematic ascertainment across CHUJANS and CAKUT cohorts recovered a urorenogenital trait in a substantial minority of individuals. The trait is variably expressive, which is why urorenal anomalies were missed in the original delineation and why the recommendation is now bidirectional: evaluate CHUJANS patients for urorenogenital malformation, and consider PHIP in syndromic CAKUT.

kidney development GO:0001822 ⚠ ABNORMAL

kidney UBERON:0002113

Downstream

Congenital Anomalies of the Kidney and Urinary Tract

Show evidence (2 references)

PMID:39156152 SUPPORT Model Organism

"The prenatal expression studies supported a role for PHIP in normal kidney and urinary tract development."

The result, not the stated aim, of the prenatal expression work. Tagged MODEL_ORGANISM because the in vivo arm is murine; the same study profiled human fetal renal tissue ex vivo, and the human clinical arm is captured by the paired item below.

PMID:39156152 SUPPORT Human Clinical

"We identified 4 novel and 8 published cases, indicating variable expressivity with a urorenogenital trait frequency of 5% to 35%."

Quantifies the human clinical frequency range of the urorenogenital trait.

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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

34

Digestive 3

Constipation FREQUENT Constipation HP:0002019

Temporal: CHRONIC

Show evidence (2 references)

PMID:37961033 SUPPORT Human Clinical

"constipation (48.9%)"

48.9% falls in the FREQUENT band.

PMID:31167805 SUPPORT Human Clinical

"a higher frequency of gastrointestinal problems, social deficits, and behavioral challenges"

Independent cohort emphasizing gastrointestinal involvement.

Gastroesophageal Reflux FREQUENT Gastroesophageal reflux HP:0002020

Show evidence (1 reference)

PMID:31167805 SUPPORT Human Clinical

"Gastrointestinal problems were also commonly reported, primarily chronic constipation (7/10) and gastroesophageal reflux disease (GERD) (4/10)."

4/10 (40%) falls in the FREQUENT band.

Feeding Difficulties FREQUENT Feeding difficulties HP:0011968

Show evidence (1 reference)

PMID:31167805 SUPPORT Human Clinical

"Feeding difficulties (7/10), hypotonia (4/10), and neonatal jaundice (3/10) were the most commonly reported neonatal issues."

7/10 (70%) falls in the FREQUENT band and identifies feeding difficulty as the leading neonatal issue.

Ear 1

Macrotia FREQUENT Macrotia HP:0000400

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"the most common features are large ears/earlobes (61%) and prominent eyebrows (61%), followed by anteverted nares (52%)"

61% falls in the FREQUENT band (30-79%), not VERY_FREQUENT - the per-feature rate is well below the 100% aggregate-gestalt rate.

PMID:31167805 SUPPORT Human Clinical

"The most common facial features were thick helices and earlobes/larger ears (8/10)"

An independent cohort in which large ears/earlobes were also the most frequent facial feature.

Endocrine 1

Hypothyroidism Hypothyroidism HP:0000821

Show evidence (2 references)

PMID:33867250 SUPPORT Human Clinical

"We present a child with the syndrome who also had hypothyroidism and renal involvement in form of small kidneys on one side."

Documents hypothyroidism in a molecularly confirmed child.

PMID:42355777 SUPPORT Human Clinical

"Laboratory investigations documented subclinical primary hypothyroidism of autoimmune origin"

An independent adult case with autoimmune subclinical primary hypothyroidism.

Eye 1

Visual Impairment FREQUENT Visual impairment HP:0000505

Show evidence (2 references)

PMID:37961033 SUPPORT Human Clinical

"visual problems (66%)"

66% falls in the FREQUENT band.

PMID:31167805 SUPPORT Human Clinical

"ophthalmologic problems were common (8/10); most commonly amblyopia (4/10) and also myopia, astigmatism, and convergence disorder."

An independent cohort giving both a concordant aggregate rate and the breakdown the larger cohort omits - amblyopia predominating, which is the finding that makes early ophthalmological referral time-critical.

Genitourinary 2

Cryptorchidism FREQUENT Cryptorchidism HP:0000028

Show evidence (1 reference)

PMID:37961033 SUPPORT Human Clinical

"cryptorchidism (39.1% of males)"

39.1% of males falls in the FREQUENT band; note the denominator is males only.

Congenital Anomalies of the Kidney and Urinary Tract OCCASIONAL Abnormality of the urinary system HP:0000079

Show evidence (3 references)

PMID:39156152 SUPPORT Human Clinical

"We identified 4 novel and 8 published cases, indicating variable expressivity with a urorenogenital trait frequency of 5% to 35%."

Gives the reported frequency range; the low end (5%) sits in the OCCASIONAL band and is used conservatively.

PMID:39156152 SUPPORT Human Clinical

"Conversely, patients with CHUJANS should be clinically evaluated for urorenogenital manifestations."

Establishes the clinical-surveillance implication of the association.

PMID:33867250 SUPPORT Human Clinical

"We present a child with the syndrome who also had hypothyroidism and renal involvement in form of small kidneys on one side."

An independent case with unilateral small kidney, an example of the renal anomaly spectrum.

Head and Neck 3

Craniofacial Dysmorphism VERY_FREQUENT Abnormal facial shape HP:0001999

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"characteristic craniofacial features (i.e. large ears/earlobes, prominent eyebrows, anteverted nares and long philtrum (23/23))"

23/23 (100%) supports the VERY_FREQUENT band. Note that the 100% denominator is for the aggregate gestalt, which is why this band is bound to the aggregate facial-shape term; the individual components are each far less frequent and carry their own, lower bands below.

PMID:36726590 SUPPORT Human Clinical

"we could establish that PHIP patients are indistinguishable based on the type of PHIP alteration (e.g. missense, loss-of-function, splice site) but show a significant difference to the average face of healthy individuals as well as to individuals with Prader-Willi syndrome (PWS, OMIM #176270) or..."

Quantifies both the discriminative power of the gestalt against key differentials and its inability to predict variant class.

Anteverted Nares FREQUENT Anteverted nares HP:0000463

Show evidence (1 reference)

PMID:36726590 SUPPORT Human Clinical

"the most common features are large ears/earlobes (61%) and prominent eyebrows (61%), followed by anteverted nares (52%)"

52% falls in the FREQUENT band.

Long Philtrum FREQUENT Long philtrum HP:0000343

Show evidence (1 reference)

PMID:36726590 SUPPORT Human Clinical

"Less frequent dysmorphism comprise a long philtrum (30%)"

30% sits at the bottom of the FREQUENT band (30-79%), far below the aggregate gestalt rate.

Limbs 1

Brachydactyly FREQUENT Brachydactyly HP:0001156

Show evidence (1 reference)

PMID:36726590 SUPPORT Human Clinical

"30% of the individuals showed brachydactyly"

30% is the lower bound of the FREQUENT band (30-79%), the same figure and therefore the same band as the long philtrum from this cohort.

Musculoskeletal 1

Hypotonia FREQUENT Hypotonia HP:0001252

Show evidence (2 references)

PMID:37961033 SUPPORT Human Clinical

"Other common symptoms were hypotonia (78.7%)"

78.7% falls in the FREQUENT band (30-79%), just below the VERY_FREQUENT threshold.

PMID:27900362 SUPPORT Human Clinical

"common clinical features of developmental delay, intellectual disability, anxiety, hypotonia, poor balance, obesity, and dysmorphic features"

Hypotonia was among the shared features in the founding report.

Nervous System 12

Global Developmental Delay VERY_FREQUENT Global developmental delay HP:0001263

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"almost all individuals reported here show developmental delay (22/23)"

22/23 (96%) supports the VERY_FREQUENT band (80-100%).

PMID:29209020 SUPPORT Human Clinical

"Remarkably, all 23 individuals had developmental delay/ID and the majority were overweight or obese."

An independent cohort in which developmental delay/ID was universal.

Intellectual Disability VERY_FREQUENT Intellectual disability HP:0001249

Show evidence (3 references)

PMID:36726590 SUPPORT Human Clinical

"learning disability or ID (22/23)"

22/23 (96%) supports the VERY_FREQUENT band.

PMID:37961033 SUPPORT Human Clinical

"Most individuals had moderately low adaptive functioning based on the Vineland-3 (mean = 76.8, standard deviation = 12.0)."

Quantifies the severity as moderately low adaptive functioning rather than severe impairment.

PMID:42355777 PARTIAL Human Clinical

"moderate-to-severe intellectual disability (full-scale IQ 38)"

Documents the severe end of the cognitive range; PARTIAL because it is a single case and does not represent the cohort-typical mild-to-moderate severity.

Delayed Speech and Language Development Delayed speech and language development HP:0000750

Show evidence (1 reference)

PMID:41383545 SUPPORT Human Clinical

"Although clinical presentations vary, behavioral problems and delayed motor and speech milestones are common."

A literature review characterizing delayed speech milestones as a common feature.

Behavioral and Psychiatric Problems VERY_FREQUENT Atypical behavior HP:0000708

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"behavioral abnormalities (20/23)"

20/23 (87%) supports the VERY_FREQUENT band. The band is deliberately bound to the aggregate behavioral-abnormality term, because no single named behavior reaches this frequency - see the separate ADHD, anxiety, depression, autistic behavior and aggression entries for the component rates.

PMID:29209020 SUPPORT Human Clinical

"Other features comprised behavioral problems (hyperactivity, aggression, features of autism and/or mood disorder)"

Enumerates the behavioral repertoire including aggression, the bound HPO term.

Aggressive Behavior OCCASIONAL Aggressive behavior HP:0000718

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"This feature has also been reported in our cohort but only in 6/23 individuals."

6/23 (26%) supports the OCCASIONAL band (5-29%), well below the 87% aggregate behavioral-abnormality rate.

PMID:36726590 SUPPORT Human Clinical

"Overall, 86.4% of our cohort show a kind of behavioral change, but aggressions seem not to be the most common one."

The authors explicitly separate the high aggregate behavioral rate from the much lower aggression rate.

Attention Deficit Hyperactivity Disorder FREQUENT Attention deficit hyperactivity disorder HP:0007018

Show evidence (2 references)

PMID:37961033 SUPPORT Human Clinical

"attention-deficit/hyperactivity disorder (51.1%)"

51.1% falls in the FREQUENT band (30-79%).

PMID:41383545 SUPPORT Human Clinical

"It is characterized by developmental delay, intellectual disability, behavioral disturbances including autism spectrum disorder and attention deficit hyperactivity disorder, obesity, and distinct facial dysmorphism such as synophrys and an upturned nose."

A dedicated case report and review confirming ADHD as a characteristic behavioral manifestation.

Anxiety FREQUENT Anxiety HP:0000739

Show evidence (2 references)

PMID:37961033 SUPPORT Human Clinical

"anxiety (46.8%)"

46.8% falls in the FREQUENT band.

PMID:27900362 SUPPORT Human Clinical

"two unrelated patients with common clinical features of developmental delay, intellectual disability, anxiety, hypotonia, poor balance, obesity, and dysmorphic features"

Anxiety was one of the shared features in the founding two-patient report.

Depression OCCASIONAL Depression HP:0000716

Show evidence (2 references)

PMID:37961033 SUPPORT Human Clinical

"depression (27.7%)"

27.7% falls in the OCCASIONAL band (5-29%).

PMID:37961033 SUPPORT Human Clinical

"Depression was significantly higher in the older age group (>12 years old)."

Establishes the age dependence that motivates ongoing surveillance.

Autistic Behavior Autistic behavior HP:0000729

Show evidence (1 reference)

PMID:29209020 SUPPORT Human Clinical

"behavioral problems (hyperactivity, aggression, features of autism and/or mood disorder)"

Features of autism are listed among the behavioral problems.

Sleep Disturbance FREQUENT Sleep disturbance HP:0002360

Show evidence (1 reference)

PMID:37961033 SUPPORT Human Clinical

"sleep difficulties (42.6%)"

42.6% falls in the FREQUENT band.

Seizure OCCASIONAL Seizure HP:0001250

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"Seizures (17.39%)"

17.39% in the 23-individual European cohort falls in the OCCASIONAL band (5-29%).

PMID:31167805 PARTIAL Human Clinical

"Seizure or suspected seizure activity were observed in four individuals."

4/10 in a smaller clinic-ascertained series, higher than the European cohort; PARTIAL because it argues for a rate above the assigned band and the two denominators are not reconciled.

Obstructive Sleep Apnea Obstructive sleep apnea HP:0002870

Severity: SEVERE

Show evidence (2 references)

PMID:41751879 SUPPORT Human Clinical

"Overnight polysomnography revealed a severe rapid eye movement-predominant obstructive sleep apnea syndrome with an apnea-hypopnea index of 31.9 events per hour"

Objective polysomnographic documentation of severe OSA in a molecularly confirmed patient.

PMID:41751879 SUPPORT Human Clinical

"This adult case provides the first polysomnographic confirmation in the syndrome, supporting proactive screening for obstructive sleep apnea-especially in those with obesity."

Establishes both the novelty of the objective confirmation and the resulting screening recommendation.

Growth 1

Obesity and Overweight FREQUENT Obesity HP:0001513

Course: PROGRESSIVE

Show evidence (4 references)

PMID:37961033 SUPPORT Human Clinical

"Overall, 55.8% of individuals were obese/overweight."

55.8% falls in the FREQUENT band (30-79%).

PMID:36726590 SUPPORT Human Clinical

"weight problems (13/23)"

13/23 (57%) in an independent European cohort, concordant with the FREQUENT band.

PMID:31167805 PARTIAL Human Clinical

"The additional individuals we report have a lower frequency of obesity than previous reports and a higher frequency of gastrointestinal problems, social deficits, and behavioral challenges."

Documents the incomplete penetrance of obesity; PARTIAL because it qualifies rather than supports a high frequency.

+ 1 more reference

Other 8

Impaired Balance and Coordination Incoordination HP:0002311

Show evidence (1 reference)

PMID:27900362 SUPPORT Human Clinical

"common clinical features of developmental delay, intellectual disability, anxiety, hypotonia, poor balance, obesity, and dysmorphic features"

Poor balance is explicitly listed among the shared clinical features.

Synophrys Synophrys HP:0000664

Show evidence (1 reference)

PMID:29209020 SUPPORT Human Clinical

"dysmorphisms (full eyebrows and/or synophrys, upturned nose, large ears and tapering fingers)"

Synophrys is explicitly listed among the syndrome's dysmorphic features.

Thick Eyebrow FREQUENT Thick eyebrow HP:0000574

Show evidence (1 reference)

PMID:36726590 SUPPORT Human Clinical

"the most common features are large ears/earlobes (61%) and prominent eyebrows (61%), followed by anteverted nares (52%)"

61% falls in the FREQUENT band; the aggregate-gestalt 100% figure does not apply to this individual feature.

Tapered Fingers Tapered finger HP:0001182

Show evidence (1 reference)

PMID:29209020 SUPPORT Human Clinical

"dysmorphisms (full eyebrows and/or synophrys, upturned nose, large ears and tapering fingers)"

Tapering fingers are explicitly listed among the dysmorphic features.

Clinodactyly of the 5th Finger FREQUENT Clinodactyly of the 5th finger HP:0004209

Show evidence (1 reference)

PMID:31167805 SUPPORT Human Clinical

"Other features included clinodactyly of the fifth finger (5/10)"

5/10 (50%) falls in the FREQUENT band.

Toe Syndactyly OCCASIONAL 2-3 toe syndactyly HP:0004691

Show evidence (1 reference)

PMID:36726590 SUPPORT Human Clinical

"26% of the individuals showed syndactyly of the second/third toes."

26% falls in the OCCASIONAL band (5-29%).

Impaired Glucose Tolerance with Hyperinsulinism Impaired glucose tolerance HP:0040270

Show evidence (1 reference)

PMID:42355777 SUPPORT Human Clinical

"impaired glucose tolerance with associated hyperinsulinism"

Documents dysglycaemia with hyperinsulinism in a molecularly confirmed patient with severe obesity.

Oligomenorrhea Oligomenorrhea HP:0000876

Show evidence (2 references)

PMID:42355777 SUPPORT Human Clinical

"referred to our centre for evaluation of oligomenorrhea in the context of severe obesity"

Documents oligomenorrhoea as the presenting endocrine complaint in a molecularly confirmed CHUJANS patient.

PMID:42355777 PARTIAL Human Clinical

"polyendocrine metabolic ovarian syndrome (PMOS, previously known as PCOS)"

The endocrine diagnosis reached; PARTIAL because the report does not state ovarian morphology, so no morphology term is bound.

🧬

Genetic Associations

1

PHIP Pathogenic Variants (Causative)

Gene: PHIP hgnc:15673 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (3 references)

PMID:29209020 SUPPORT Human Clinical

"Amongst these, PHIP was shown to have an enrichment of disruptive mutations in the individuals with ID (5 out of 3,275)."

The statistical gene-level enrichment in an intellectual-disability cohort that established PHIP as an ID gene.

PMID:31167805 SUPPORT Human Clinical

"We report an additional 10 individuals with pleckstrin homology domain-interacting protein (PHIP)-predicted deleterious variants (four frameshift, three missense, two nonsense, and one splice site; six of which are confirmed de novo)."

Enumerates the variant classes and the de novo proportion in an independent series.

PMID:41383545 SUPPORT Human Clinical

"Whole Exome Sequencing revealed pathogenic mutations in both the PHIP and CLCN4 genes."

Supports the dual-diagnosis caveat in the notes: an atypically severe presentation was explained by a second pathogenic locus, not by PHIP expressivity alone.

💊

Medical Actions

8

Multidisciplinary Developmental and Supportive Care

Category: Therapeutic Action: supportive care Ontology label: Supportive Care NCIT:C15747

There is no disease-modifying or PHIP-targeted therapy. Management is symptomatic, developmental, and anticipatory: early-intervention services, individualized educational support, therapy for hypotonia and motor delay, feeding and gastrointestinal support, ophthalmological assessment, and coordinated behavioral-health care. The distinctive planning message from the natural-history data is that the burden shifts with age - weight and mood problems become more prominent after childhood - so care should be structured for the life course rather than front-loaded into the preschool years.

Target Phenotypes: Global developmental delay HP:0001263

Show evidence (1 reference)

PMID:37961033 SUPPORT Human Clinical

"Our findings provide additional natural history data for Chung-Jansen syndrome and provide opportunities for early intervention of healthy eating habits and awareness of developing mood and behavioral challenges over the life course."

The cohort's own framing of management as early intervention plus life-course awareness.

Speech and Language Therapy

Category: Therapeutic Action: speech therapy Ontology label: Speech Language Therapy NCIT:C159273

Speech and language therapy addresses the delayed speech milestones that are a common early feature and a frequent reason for referral.

Target Phenotypes: Delayed speech and language development HP:0000750

Show evidence (1 reference)

PMID:41383545 PARTIAL Human Clinical

"Although clinical presentations vary, behavioral problems and delayed motor and speech milestones are common."

Establishes the speech-delay indication; PARTIAL because no CHUJANS-specific speech-therapy outcome study exists.

Physical Therapy

Category: Therapeutic Action: physical therapy Ontology label: Physical Therapy NCIT:C15302

Physiotherapy targets the hypotonia, motor delay, and balance/coordination difficulty that affect the large majority of individuals. The rationale is the documented motor phenotype; no CHUJANS-specific rehabilitation trial exists.

Target Phenotypes: Hypotonia HP:0001252

Show evidence (1 reference)

PMID:37961033 PARTIAL Human Clinical

"Other common symptoms were hypotonia (78.7%)"

Documents the indication (hypotonia in ~79%); PARTIAL because the therapy itself is not evaluated in the source.

Occupational Therapy

Category: Therapeutic Action: occupational therapy Ontology label: Occupational Therapy NCIT:C121351

Occupational therapy addresses fine-motor and daily-living function. It is curated separately from physiotherapy because the adaptive-functioning data give it its own indication: daily-living-skills percentiles were low across the cohort, and socialisation scores were low in every individual assessed, so the functional deficit is not reducible to the motor phenotype physiotherapy addresses.

Target Phenotypes: Global developmental delay HP:0001263

Show evidence (1 reference)

PMID:31167805 PARTIAL Human Clinical

"age-adjusted percentiles varied in communication (1%-42%; average:11.8%, median: 8%) and daily living skills (1%-50%; average: 12.6%, median 4%)"

Quantifies the daily-living-skills deficit that occupational therapy targets; PARTIAL because the therapy itself is not evaluated in the source.

Early Dietary and Weight-Management Intervention

Category: Therapeutic Action: dietary intervention Ontology label: Dietary Intervention NCIT:C15447

Because overweight and obesity emerge over time rather than being present from birth and become more prevalent after age 12, the natural-history data argue for establishing healthy eating habits early - before weight problems appear - rather than treating obesity reactively. This is the one management recommendation that follows directly from the syndrome's own mechanistic and longitudinal data (reduced POMC-melanocortin satiety signaling with age-dependent weight gain), and it is preventive in intent.

Mechanism Target:

INHIBITS Obesity and Overweight — Behavioral energy-balance management does not correct the upstream melanocortin deficit; it opposes the downstream weight outcome by constraining energy intake. The edge therefore targets the weight node rather than the satiety-signaling node, where an INHIBITS edge would read backwards.

Target Phenotypes: Obesity HP:0001513

Show evidence (1 reference)

PMID:37961033 SUPPORT Human Clinical

"provide opportunities for early intervention of healthy eating habits"

The explicit dietary-intervention recommendation from the natural-history cohort.

Continuous Positive Airway Pressure for Obstructive Sleep Apnea

Category: Therapeutic Action: continuous positive airway pressure Ontology label: Continuous Positive Airway Pressure NCIT:C124040

In the one CHUJANS patient with polysomnographically confirmed severe REM-predominant obstructive sleep apnea, CPAP improved respiratory and sleep quality indices and was well tolerated - which matters because tolerance of positive-airway-pressure therapy cannot be assumed in a population with intellectual disability. Evidence is a single case.

Target Phenotypes: Obstructive sleep apnea HP:0002870

Show evidence (1 reference)

PMID:41751879 SUPPORT Human Clinical

"Treatment with continuous positive airway pressure improved respiratory and sleep quality indices and was well tolerated."

Direct outcome evidence for CPAP in a molecularly confirmed CHUJANS patient.

Longitudinal Behavioral-Health, Weight, and Urorenal Surveillance

Category: Screening Action: complication surveillance Ontology label: Disease Screening NCIT:C15419

Three surveillance streams are specifically indicated by the CHUJANS literature rather than by generic syndromic practice: mood and behavior into adolescence and adulthood, because depression is significantly more frequent after age 12; BMI over time, because obesity emerges and increases with age; and urorenogenital evaluation, because CAKUT is a variably expressive part of the spectrum that was missed in the original delineation. Endocrine assessment (thyroid function, glucose tolerance, reproductive endocrine status) has also been proposed on the basis of a detailed adult workup. Recorded with the generic NCIT disease-screening action because NCIT has no clinical-intervention term for longitudinal surveillance.

Show evidence (3 references)

PMID:37961033 SUPPORT Human Clinical

"awareness of developing mood and behavioral challenges over the life course"

Supports the behavioral-health surveillance stream.

PMID:39156152 SUPPORT Human Clinical

"Conversely, patients with CHUJANS should be clinically evaluated for urorenogenital manifestations."

Supports the urorenal surveillance stream.

PMID:42355777 PARTIAL Human Clinical

"This case suggests the inclusion of comprehensive endocrine evaluations in future studies on patients with Chung-Jansen syndrome, in order to support endocrine work-up and facilitate early identification and appropriate management of potentially treatable alterations."

Proposes endocrine surveillance; PARTIAL because it is a single-case recommendation framed as a suggestion for future study.

Genetic Counseling and Parental Testing

Category: Counseling / Informational Action: genetic counseling Ontology label: Genetic Counseling NCIT:C15240

Counseling must cover the 50% transmission risk for an affected heterozygote and, more subtly, the fact that a clinically unremarkable parent may nonetheless carry the variant - inherited alleles from mildly affected parents are well documented, and severity cannot be predicted from genotype. Parental testing is therefore not optional bookkeeping but the step that determines recurrence risk and identifies previously undiagnosed relatives.

Show evidence (2 references)

PMID:36726590 SUPPORT Human Clinical

"outlines the importance of a thorough clinical evaluation combined with genetic analyses for accurate diagnosis and counselling"

The cohort's explicit counseling recommendation, grounded in the observed inherited cases.

PMID:39437749 SUPPORT Human Clinical

"Our finding expands the spectrum of disease-causing variants in PHIP and demonstrates variable intrafamilial clinical expressivity and severity."

Documents the intrafamilial variability that counseling must convey.

🔀

Differential Diagnoses

6

Conditions with similar clinical presentations that must be differentiated from Chung-Jansen Syndrome:

Prader-Willi syndrome MONDO:0008300

Overlapping Features The archetypal intellectual-disability-plus-obesity syndrome and the first differential a clinician will reach for. Discriminators favouring Prader-Willi are neonatal hypotonia with failure to thrive followed by a distinct hyperphagic phase, hypogonadism, short stature, and the 15q11-q13 imprinting mechanism. Objective facial phenotyping separates the two: PHIP patients differ significantly from the average Prader-Willi face.

Show evidence (1 reference)

PMID:36726590 SUPPORT Human Clinical

"show a significant difference to the average face of healthy individuals as well as to individuals with Prader-Willi syndrome (PWS, OMIM #176270)"

GestaltMatcher analysis explicitly separates the CHUJANS facial gestalt from Prader-Willi.

X-linked intellectual disability, Cabezas type (CUL4B) Not Yet Curated MONDO:0010306

Overlapping Features Mechanistically the closest neighbour: CUL4B is the cullin scaffold of the very CRL4 ligase for which PHIP is a substrate receptor, and CUL4B deficiency causes intellectual disability with central obesity, muscle wasting, and dysmorphism - an overlap that was itself used as an argument that PHIP acts through the ubiquitin ligase pathway. Discriminators are the X-linked inheritance and male predominance of the CUL4B disorder; facial phenotyping also separates the two.

Show evidence (2 references)

PMID:27900362 SUPPORT Human Clinical

"CUL4B deficiency has been associated with intellectual disability, central obesity, muscle wasting, and dysmorphic features."

States the overlapping CUL4B phenotype that makes it a differential and a mechanistic neighbour.

PMID:36726590 SUPPORT Human Clinical

"or with a CUL4B-alteration (Intellectual developmental disorder, X-linked, syndromic, Cabezas type, OMIM #300354)"

Facial phenotyping separates CHUJANS from the CUL4B disorder.

Cornelia de Lange syndrome MONDO:0016033

Overlapping Features The prominent/full eyebrows with synophrys, anteverted nares, and long philtrum make CHUJANS a genuine phenocopy of the CdLS facial gestalt, and at least one family was worked up as CdLS - with an initially negative CdLS-focused exome reanalysis - before the PHIP variant was found. Discriminators favouring CdLS are upper-limb reduction defects, marked growth restriction, hirsutism, and cohesin-complex genes. The published recommendation is to include PHIP in CdLS-spectrum gene analysis.

Show evidence (2 references)

PMID:36843271 SUPPORT Human Clinical

"CHUJANS shows a significant overlap with the CdLS spectrum, with specific regard to facial gestalt."

Establishes the facial overlap that drives the diagnostic confusion.

PMID:36843271 SUPPORT Human Clinical

"we suggest to include PHIP among genes routinely analyzed in patients belonging to the CdLS spectrum"

The practical testing recommendation that follows from the overlap.

Borjeson-Forssman-Lehmann syndrome (PHF6) MONDO:0010537

Overlapping Features An X-linked intellectual disability syndrome with obesity that is both a clinical and a molecular neighbour: its DNA methylation episignature partially overlaps that of CHUJANS, and a combined episignature covering both disorders (plus White-Kernohan syndrome) has been developed. This overlap is not coincidence - PHF6, like PHIP, is a chromatin-associated protein - which is precisely why an episignature result should be interpreted as evidence about this functional group rather than as a single-gene readout.

Show evidence (1 reference)

PMID:38787418 SUPPORT Human Clinical

"Börjeson-Forssman-Lehmann syndrome (caused by variants in PHF6 gene)"

Named as one of the two functionally related, clinically partially overlapping disorders sharing methylation-profile similarity with CHUJANS.

White-Kernohan syndrome (DDB1) Not Yet Curated MONDO:0859169

Overlapping Features Caused by variants in DDB1, the CRL4 adaptor that PHIP itself docks onto as a substrate receptor - so this is the most direct pathway-level differential in the set. It shares a partially overlapping methylation episignature with CHUJANS, and the two are handled together in the combined episignature classifier.

Show evidence (1 reference)

PMID:38787418 SUPPORT Human Clinical

"White-Kernohan syndrome (caused by variants in DDB1 gene)"

Named as the other functionally related disorder sharing an overlapping episignature; DDB1 is the CRL4 adaptor PHIP works through.

Pitt-Hopkins syndrome (TCF4) MONDO:0012589

Overlapping Features Not a classical CHUJANS differential, but added because a child whose craniofacial phenotype and Face2Gene analysis both suggested a Pitt-Hopkins-like condition was found instead to carry a novel PHIP variant, expanding the recognized phenotypic spectrum. The lesson is that facial-analysis software pointing away from CHUJANS does not exclude it.

Show evidence (1 reference)

PMID:39594970 SUPPORT Human Clinical

"The unusual clinical presentation of this novel patient resembles a PTHS-like condition. However, a novel variant in PHIP has been unexpectedly detected, expanding the phenotypic spectrum of CHUJANS."

Documents the PTHS-like presentation resolved as CHUJANS.

🔬

Clinical Trials

1

NCT01238250

Simons Searchlight, an international online observational registry that collects medical, behavioral, learning, and developmental data plus biospecimens from families with rare genetic variants causing neurodevelopmental disorders. It is the main real-world data-collection route available to CHUJANS families and the most concrete existing mechanism for overcoming the small-cohort problem in this disorder. It is observational and does not test any treatment.

Show evidence (1 reference)

clinicaltrials:NCT01238250 PARTIAL Other

"Simons Searchlight is an observational, online, international research program for families with rare genetic variants that cause neurodevelopmental disorders and may be associated with autism."

Confirms the registry's design and scope. Support is PARTIAL because the cached ClinicalTrials.gov record describes eligibility generically as rare genetic variants that cause neurodevelopmental disorders and does not itself name PHIP, so PHIP-specific eligibility is not verifiable from this record.

{ }

Source YAML

click to show

name: Chung-Jansen Syndrome
creation_date: "2026-08-01T18:45:00Z"
synonyms:
- CHUJANS
- PHIP-associated Chung-Jansen syndrome
- PHIP-related behavioral problems-intellectual disability-obesity-dysmorphic features syndrome
- Developmental delay, intellectual disability, obesity, and dysmorphic features
- DIDOD syndrome
- BIDOD syndrome
- PHIP haploinsufficiency syndrome
- Intellectual disability-overweight syndrome
description: >-
  Chung-Jansen syndrome (CHUJANS; OMIM #617991) is a rare autosomal dominant
  neurodevelopmental disorder caused by heterozygous loss-of-function variants in
  PHIP. PHIP is not a chromatin writer or eraser but a multivalent chromatin
  reader: it binds the nucleosome through a trivalent module - an H3K4-methyl
  binding Tudor domain plus two bromodomains that read H3K14ac (BD1) and H4K12ac
  (BD2) - and, so bound, serves as the chromatin-associated substrate receptor
  (DCAF14) that recruits the CRL4 ubiquitin ligase to chromatin. Disease-associated
  variants fall in each of these reader domains and in the intervening linker,
  placing CHUJANS squarely in the chromatinopathy / epigenetic-machinery class of
  neurodevelopmental disorders rather than among generic NDD genes. Consistent with
  that placement, affected individuals carry a specific and sensitive DNA
  methylation episignature that partially overlaps the episignatures of two other
  functionally related disorders in the same axis, Borjeson-Forssman-Lehmann
  syndrome (PHF6) and White-Kernohan syndrome (DDB1, the CRL4 adaptor PHIP works
  through). The clinical core is developmental delay with mild-to-moderate learning
  disability or intellectual disability, behavioral and psychiatric problems
  (prominently ADHD, anxiety, and later depression), a recognizable craniofacial
  gestalt (large ears/earlobes, prominent eyebrows and synophrys, anteverted nares,
  long philtrum), hypotonia, and childhood- to puberty-onset overweight or obesity.
  Obesity is the best-explained feature mechanistically: nuclear PHIP directly
  enhances transcription of POMC, and disease-associated variants repress it,
  connecting PHIP dosage to central leptin-melanocortin satiety signaling. A
  separate arm of PHIP/DCAF14 biology - replication fork protection under
  replication stress - is also disrupted by patient variants. Expressivity is wide:
  a substantial minority of alleles are inherited from a mildly affected parent, and
  obesity is not obligatory.
category: Mendelian
classifications:
  harrisons_chapter:
  - classification_value: GENETICS_ENVIRONMENT_DISEASE
    notes: >-
      A monogenic, autosomal dominant Mendelian disorder identified and diagnosed by
      exome/genome sequencing and chromosomal microarray.
    evidence:
    - reference: PMID:29209020
      reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        highlighted by PHIP haploinsufficiency causing an ID-overweight syndrome
      explanation: >-
        Establishes the entity as a monogenic haploinsufficiency syndrome delineated
        by targeted re-sequencing and reverse phenotyping.
  - classification_value: NEUROLOGIC
    notes: >-
      The dominant clinical burden is neurodevelopmental and behavioral:
      developmental delay, intellectual disability, hypotonia, and psychiatric
      comorbidity.
    evidence:
    - reference: PMID:37961033
      reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Individuals in this cohort frequently had a history of developmental delay
        (85.1%), attention-deficit/hyperactivity disorder (51.1%), anxiety (46.8%),
        depression (27.7%), and sleep difficulties (42.6%).
      explanation: >-
        The most frequent manifestations in the largest natural-history cohort are
        neurodevelopmental and neuropsychiatric.
  - classification_value: ENDOCRINOLOGY_METABOLISM
    notes: >-
      Overweight/obesity is a defining component of the syndrome and the arm with the
      clearest molecular mechanism (POMC/melanocortin), with downstream metabolic and
      endocrine comorbidity.
    evidence:
    - reference: PMID:32492392
      reference_title: "Exome Sequencing Identifies Genes and Gene Sets Contributing to Severe Childhood Obesity, Linking PHIP Variants to Repressed POMC Transcription."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Using exome and targeted sequencing in 2,737 severely obese cases and 6,704
        controls, we identified three genes (PHIP, DGKI, and ZMYM4) with an excess
        burden of very rare predicted deleterious variants in cases.
      explanation: >-
        Human genetic evidence placing PHIP in the severe-obesity / energy-homeostasis
        axis alongside the syndromic obesities.
disease_term:
  preferred_term: Chung-Jansen syndrome
  term:
    id: MONDO:0035133
    label: PHIP-related behavioral problems-intellectual disability-obesity-dysmorphic features syndrome
parents:
- autosomal dominant syndromic intellectual disability
- chromatinopathy
- syndromic obesity

notes: >-
  Naming. The file and entry use "Chung-Jansen Syndrome", the eponym in universal
  clinical and literature use (it is an EXACT synonym of MONDO:0035133, sourced from
  both OMIM:617991 and Orphanet:589905, and is the title term of essentially every
  cohort paper since 2022). The MONDO primary label is the long descriptive
  "PHIP-related behavioral problems-intellectual disability-obesity-dysmorphic
  features syndrome"; that string is retained verbatim as the bound term.label and
  as a synonym, but is not usable as a display name. Earlier literature also used
  the acronyms DIDOD and BIDOD.

  GeneReviews. No GeneReviews chapter exists for Chung-Jansen syndrome or PHIP
  (PubMed searches for "Chung-Jansen GeneReviews" and "PHIP gene GeneReviews"
  returned zero records on 2026-08-01). The phenotype baseline for this entry is
  therefore the primary cohort literature: Jansen 2018 (n=23), Kampmeier 2022
  (n=23), and Sudnawa 2024 (n=47, the largest and most quantitative).

  Prevalence. Orphanet has a record (ORPHA:589905) but no Orphadata-derived
  prevalence row is available in this repository's cache and the Orphadata refresh is
  currently broken on a manifest checksum, so only a qualitative literature-based
  band is recorded.

  Numbers not carried over. The Edison deep-research report quoted several figures
  from Marenne et al. full text (burden-test odds ratio and p-value, the specific
  dominant-negative variant list, the nuclear-to-cytoplasmic ratio p-value, and mouse
  Phip-null growth/survival data) that are not present in the cached abstract. Those
  were deliberately excluded from both snippets and prose rather than asserted from
  an unverifiable source.

inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    Heterozygous PHIP variants act dominantly through haploinsufficiency. Most
    probands carry de novo alleles, but a consistent minority are inherited from a
    mildly affected parent, and multigenerational segregation has been documented -
    so a normal-appearing parent should not be assumed to be a non-carrier without
    testing. Penetrance for the neurodevelopmental core appears high; penetrance for
    obesity specifically is incomplete.
  expressivity: VARIABLE
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Variants were de novo in 61.7%, unknown inheritance in 29.8%, and inherited in
      8.5%.
    explanation: >-
      Quantifies the de novo versus inherited split in the largest reported cohort.
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Follow-up investigations (e.g. Sanger sequencing, qPCR or
      Fluorescence-in-situ-Hybridization) and segregation analysis showed either de
      novo occurrence or inheritance from an also (mildly) affected parent.
    explanation: >-
      Documents both de novo origin and transmission from a mildly affected parent in
      the same European cohort.
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The fact that some variants were inherited from a mildly affected parent
      further illustrates the variability of the associated phenotype
    explanation: >-
      Directly supports the VARIABLE expressivity assignment.
  - reference: PMID:39437749
    reference_title: "Novel Insights: A Novel PHIP Variant in a Family with Severe Early-Onset Obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Further genetic testing in family members revealed segregation of the same PHIP
      variant in the brother and mother, who both presented with severe childhood
      obesity and developmental delay or learning difficulties.
    explanation: >-
      A three-member family with the same allele demonstrates dominant vertical
      transmission and intrafamilial variability.

mechanistic_hypotheses:
- hypothesis_group_id: chromatin_reader_crl4_recruitment
  hypothesis_label: Trivalent Chromatin Reading and CRL4 Recruitment Failure Branch
  status: CANONICAL
  description: >-
    The canonical molecular lesion is loss of PHIP's activity as a multivalent
    chromatin reader. PHIP engages the nucleosome through three coordinated reader
    surfaces - a Tudor domain reading H3K4 methylation, BD1 reading H3K14ac, and BD2
    reading H4K12ac - and it is this chromatin engagement that allows PHIP to act as
    the substrate receptor recruiting the CRL4 ubiquitin ligase to chromatin.
    Disease-associated PHIP variants map into each reader domain and into the linker
    between them, and are predicted to disrupt chromatin binding. This is the branch
    that makes CHUJANS a chromatinopathy rather than a generic NDD, and it is
    corroborated at the patient level by the disorder's DNA methylation episignature
    and by that signature's overlap with the PHF6 and DDB1 disorders.
  evidence:
  - reference: PMID:34819353
    reference_title: "A trivalent nucleosome interaction by PHIP/BRWD2 is disrupted in neurodevelopmental disorders and cancer."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      PHIP binds to chromatin through a trivalent reader domain consisting of a
      H3K4-methyl binding Tudor domain and two bromodomains (BD1 and BD2).
    explanation: >-
      Defines the trivalent reader architecture that this hypothesis branch is built
      on.
- hypothesis_group_id: pomc_melanocortin_repression
  hypothesis_label: POMC Repression / Central Melanocortin Branch
  status: EMERGING
  description: >-
    The obesity arm has its own, mechanistically distinct and comparatively
    well-developed model: nuclear PHIP directly enhances transcription of POMC, the
    precursor of the anorexigenic melanocortin peptides, and obesity-associated PHIP
    variants repress POMC transcription - linking PHIP dosage to central
    leptin-melanocortin satiety signaling. The status is EMERGING rather than
    CANONICAL because the demonstration is cell-based rather than in human
    hypothalamic POMC neurons, and because obesity is not fully penetrant in
    CHUJANS. This branch is not a competitor to the chromatin-reader branch; it is
    plausibly a tissue-specific readout of the same transcriptional-coactivator
    deficit, but that connection has not been shown directly.
  evidence:
  - reference: PMID:32492392
    reference_title: "Exome Sequencing Identifies Genes and Gene Sets Contributing to Severe Childhood Obesity, Linking PHIP Variants to Repressed POMC Transcription."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      In cells, we found that nuclear PHIP (pleckstrin homology domain interacting
      protein) directly enhances transcription of pro-opiomelanocortin (POMC), a
      neuropeptide that suppresses appetite. Obesity-associated PHIP variants
      repressed POMC transcription.
    explanation: >-
      The primary functional result underpinning this branch, and the explicit basis
      for its IN_VITRO evidence tag.
- hypothesis_group_id: replication_stress_genome_integrity
  hypothesis_label: Replication Fork Protection / Genome Integrity Branch
  status: EMERGING
  description: >-
    Full-length PHIP is also DCAF14, a replication stress response protein. Two
    CHUJANS missense variants in different functional elements (the WD40 repeat
    domain and the pleckstrin-homology-binding region) both cause defective
    replication fork progression under replication stress and fail to complete DNA
    replication after genotoxic insult. Whether this replication-associated genome
    instability contributes to the clinical phenotype - as opposed to being a
    parallel consequence of the same protein loss - is unresolved; no
    CHUJANS-specific cancer predisposition or chromosome-instability clinical
    phenotype has been established.
  evidence:
  - reference: PMID:35863899
    reference_title: "PHIP variants associated with Chung-Jansen syndrome disrupt replication fork stability and genome integrity."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Using DNA fiber assays, we reveal that cells expressing either variant exhibit
      defective replication fork progression in conditions of replication stress.
    explanation: >-
      Establishes the replication-stress defect for patient-derived CHUJANS alleles.

pathophysiology:
- name: Heterozygous PHIP Loss-of-Function Variation
  description: >-
    The initiating lesion is a heterozygous, usually germline PHIP variant at 6q14.1.
    The allelic spectrum is broad and shows no clustering hotspot: nonsense and
    frameshift truncations, splice variants, missense substitutions, and intragenic,
    whole-gene, or contiguous deletions extending into adjacent genomic regions are
    all reported. Larger deletions can produce a blended phenotype because
    neighbouring genes are co-deleted.
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  genes:
  - preferred_term: PHIP
    term:
      id: hgnc:15673
      label: PHIP
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      including, truncating variants, missense substitutions, splice variants and
      large deletions encompassing portions of the gene or the entire gene as well as
      adjacent genomic regions
    explanation: >-
      Enumerates the reported allelic classes, including structural alleles.
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The mutation spectrum is diverse, and there is no clustering of mutations
      across the protein.
    explanation: >-
      Establishes the absence of a mutational hotspot, which is why the entry models
      dosage loss rather than a domain-restricted allele class.
  downstream:
  - target: PHIP Haploinsufficiency
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:27900362
      reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Patients with microdeletions of 6q14.1, including PHIP, have a similar
        phenotype of developmental delay, intellectual disability, hypotonia, and
        obesity, suggesting that the phenotype of our patients is a result of
        loss-of-function mutations.
      explanation: >-
        The convergence of point alleles and whole-gene deletions on one phenotype is
        the classic argument that the operative consequence is loss of function.

- name: PHIP Haploinsufficiency
  description: >-
    Loss of one functional PHIP allele halves the dose of the chromatin-reader /
    CRL4 substrate receptor. Haploinsufficiency, not a gain of function, is the
    accepted mechanism, and the genotype-phenotype analysis that delineated the
    syndrome assigned the causal isoform specifically to PHIP/DCAF14 rather than to
    the alternative NDRP product of the same locus. The same locus additionally
    encodes a protein implicated in IGF-1 signalling, so PHIP dosage loss is not
    confined to the nuclear chromatin arm.
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  genes:
  - preferred_term: PHIP
    term:
      id: hgnc:15673
      label: PHIP
  evidence:
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Detailed genotype-phenotype analysis points towards haploinsufficiency of
      PHIP/DCAF14, and not NDRP, as the underlying cause of the phenotype.
    explanation: >-
      Assigns haploinsufficiency, and specifically the PHIP/DCAF14 isoform, as the
      disease mechanism.
  - reference: PMID:39156152
    reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The neurodevelopmental disorder Chung-Jansen syndrome (CHUJANS) is caused by
      haploinsufficiency of Pleckstrin homology domain-interacting protein (PHIP)
    explanation: >-
      Independent restatement of haploinsufficiency as the established mechanism.
  - reference: PMID:42355777
    reference_title: "Chung-Jansen Syndrome in a Young Woman with a PHIP Variant: Severe Obesity, Intellectual Disability, and Endocrine Abnormalities."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      which encodes a protein involved in neurodevelopmental processes and IGF-1
      signalling
    explanation: >-
      Notes the second, non-chromatin (IGF-1 signalling) function attributed to the
      PHIP products; PARTIAL because that arm is not developed into a curated
      pathophysiology node for lack of CHUJANS-specific mechanistic evidence.
  downstream:
  - target: Impaired Trivalent Nucleosome Reading by the PHIP Tudor-Bromodomain Module
    causal_link_type: DIRECT
    hypothesis_groups:
    - chromatin_reader_crl4_recruitment
    evidence:
    - reference: PMID:34819353
      reference_title: "A trivalent nucleosome interaction by PHIP/BRWD2 is disrupted in neurodevelopmental disorders and cancer."
      supports: PARTIAL
      evidence_source: IN_VITRO
      snippet: >-
        we characterize PHIPs BD1 and BD2 as respective readers of H3K14ac and
        H4K12ac, and identify human disease-associated mutations in each domain and
        the intervening linker region that likely disrupt chromatin binding
      explanation: >-
        Disease alleles are located in the reader domains themselves, so reduced PHIP
        dose translates directly into reduced nucleosome reading.
  - target: Repressed POMC Transcription
    causal_link_type: DIRECT
    hypothesis_groups:
    - pomc_melanocortin_repression
    evidence:
    - reference: PMID:32492392
      reference_title: "Exome Sequencing Identifies Genes and Gene Sets Contributing to Severe Childhood Obesity, Linking PHIP Variants to Repressed POMC Transcription."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Obesity-associated PHIP variants repressed POMC transcription.
      explanation: >-
        Patient-type PHIP alleles reduce POMC transcriptional output in cells.
  - target: Replication Fork Destabilization Under Replication Stress
    causal_link_type: DIRECT
    hypothesis_groups:
    - replication_stress_genome_integrity
    evidence:
    - reference: PMID:35863899
      reference_title: "PHIP variants associated with Chung-Jansen syndrome disrupt replication fork stability and genome integrity."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Full length PHIP, also called DCAF14, was recently identified to function as
        a replication stress response protein.
      explanation: >-
        Identifies the second, replication-associated function that PHIP dosage loss
        compromises.
  - target: Disrupted PHIP-Dependent Kidney and Urinary Tract Development
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39156152
      reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The neurodevelopmental disorder Chung-Jansen syndrome (CHUJANS) is caused by
        haploinsufficiency of Pleckstrin homology domain-interacting protein (PHIP)
        and was previously associated with genital malformations.
      explanation: >-
        Attaches the urorenogenital developmental arm to the same haploinsufficiency
        trigger as the other three arms.

- name: Impaired Trivalent Nucleosome Reading by the PHIP Tudor-Bromodomain Module
  description: >-
    PHIP is a BRD/BRWD-family multivalent chromatin reader. Semisynthetic nucleosomes
    with defined histone modifications show that its three reader surfaces are
    non-redundant and combinatorial: a Tudor domain reads H3K4 methylation, the first
    bromodomain (BD1) reads acetylated H3K14, and the second bromodomain (BD2) reads
    acetylated H4K12. Because CHUJANS variants occur in each of these domains and in
    the linker that positions them relative to one another, the primary molecular
    defect is failure to engage appropriately marked nucleosomes - a reading defect,
    not a writing or erasing defect. Note the epistemic split within this node: the
    reader architecture and its mark specificities are measured biochemistry, whereas
    the impairment of that reading by patient alleles is inferred from variant
    location and is described by the source as likely rather than demonstrated -
    hence PROVISIONAL rather than ESTABLISHED confidence.
  biological_scale: MOLECULAR
  mechanism_confidence: PROVISIONAL
  molecular_functions:
  - preferred_term: H3K4-methyl binding Tudor domain reader activity
    term:
      id: GO:0140002
      label: histone H3K4me3 reader activity
    modifier: DECREASED
  - preferred_term: PHIP bromodomain 1 (BD1) reading of H3K14ac
    term:
      id: GO:0140015
      label: histone H3K14ac reader activity
    modifier: DECREASED
  - preferred_term: PHIP bromodomain 2 (BD2) reading of H4K12ac
    term:
      id: GO:0140011
      label: histone H4K12ac reader activity
    modifier: DECREASED
  - preferred_term: chromatin binding
    term:
      id: GO:0003682
      label: chromatin binding
    modifier: DECREASED
  evidence:
  - reference: PMID:34819353
    reference_title: "A trivalent nucleosome interaction by PHIP/BRWD2 is disrupted in neurodevelopmental disorders and cancer."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Using semisynthetic nucleosomes with defined histone post-translational
      modifications, we characterize PHIPs BD1 and BD2 as respective readers of
      H3K14ac and H4K12ac, and identify human disease-associated mutations in each
      domain and the intervening linker region that likely disrupt chromatin binding.
    explanation: >-
      Assigns the specific acetyl-lysine marks read by each bromodomain and localizes
      disease variants to those reader modules.
  - reference: PMID:34819353
    reference_title: "A trivalent nucleosome interaction by PHIP/BRWD2 is disrupted in neurodevelopmental disorders and cancer."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Mutations in the PHIP/BRWD2 chromatin regulator cause the human
      neurodevelopmental disorder Chung-Jansen syndrome
    explanation: >-
      Frames PHIP explicitly as a chromatin regulator and ties it to this disorder.
  downstream:
  - target: Failure of CRL4 Substrate-Receptor Recruitment to Chromatin
    causal_link_type: DIRECT
    hypothesis_groups:
    - chromatin_reader_crl4_recruitment
    evidence:
    - reference: PMID:34819353
      reference_title: "A trivalent nucleosome interaction by PHIP/BRWD2 is disrupted in neurodevelopmental disorders and cancer."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Here we demonstrate that PHIP is a chromatin-associated CRL4 ubiquitin ligase
        substrate receptor and is required for CRL4 recruitment to chromatin.
      explanation: >-
        The chromatin-reading step is what licenses CRL4 recruitment, so losing the
        former directly impairs the latter.

- name: Failure of CRL4 Substrate-Receptor Recruitment to Chromatin
  description: >-
    PHIP (as DCAF14) is one of several substrate receptors of the
    CUL4-DDB1 (CRL4) E3 ubiquitin ligase, and it is specifically the
    chromatin-associated one - PHIP is required for CRL4 to be recruited to
    chromatin at all. Reduced PHIP dose therefore removes chromatin-localized CRL4
    activity, with consequences for ubiquitin-dependent turnover of chromatin
    substrates and for chromatin-templated transcription. The clinical corroboration
    of this node is the phenotypic overlap of PHIP loss with CUL4B deficiency, which
    likewise causes intellectual disability with central obesity and dysmorphism.
  biological_scale: MOLECULAR
  mechanism_confidence: PROVISIONAL
  cellular_components:
  - preferred_term: CRL4 (CUL4-DDB1) E3 ubiquitin ligase complex
    term:
      id: GO:0080008
      label: Cul4-RING E3 ubiquitin ligase complex
  biological_processes:
  - preferred_term: chromatin-associated protein ubiquitination
    term:
      id: GO:0016567
      label: protein ubiquitination
    modifier: DECREASED
  - preferred_term: regulation of transcription by RNA polymerase II
    term:
      id: GO:0006357
      label: regulation of transcription by RNA polymerase II
    modifier: ABNORMAL
  evidence:
  - reference: PMID:35863899
    reference_title: "PHIP variants associated with Chung-Jansen syndrome disrupt replication fork stability and genome integrity."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      CJS is associated with heterozygous variants in PHIP (Pleckstrin-Homology
      Interacting Protein), a gene that encodes one of several substrate receptors
      for Cullin4-RING (CRL4) E3 ubiquitin ligase complex.
    explanation: >-
      Establishes PHIP's identity as a CRL4 substrate receptor.
  - reference: PMID:27900362
    reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The overlapping phenotype associated with CUL4B deficiency suggests that PHIP
      mutations cause disease through disruption of the ubiquitin ligase pathway.
    explanation: >-
      Human-genetic corroboration: another component of the same ligase, when lost,
      produces an overlapping ID-plus-central-obesity phenotype.
  downstream:
  - target: Chung-Jansen DNA Methylation Episignature
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    hypothesis_groups:
    - chromatin_reader_crl4_recruitment
    evidence:
    - reference: PMID:38787418
      reference_title: "The detection of a strong episignature for Chung-Jansen syndrome, partially overlapping with Borjeson-Forssman-Lehmann and White-Kernohan syndromes."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        It is caused by pathogenic variants in the PHIP gene that encodes for the
        Pleckstrin homology domain-interacting protein, which is part of an
        epigenetic modifier protein complex. Therefore, we hypothesized that PHIP
        haploinsufficiency may impact genome-wide DNA methylation (DNAm).
      explanation: >-
        The episignature study's own stated rationale is that loss of this
        epigenetic-complex component propagates to genome-wide methylation; the
        intervening steps are not resolved.
  - target: Disrupted Neurodevelopmental Gene Expression Program
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    hypothesis_groups:
    - chromatin_reader_crl4_recruitment
    evidence:
    - reference: PMID:29209020
      reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
      supports: PARTIAL
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Interestingly, PHIP encodes two protein-isoforms, PHIP/DCAF14 and NDRP, each
        involved in neurodevelopmental processes, including E3 ubiquitination and
        neuronal differentiation.
      explanation: >-
        Links the E3-ubiquitination arm to neurodevelopmental processes; support is
        PARTIAL because no patient-neuron transcriptomic dataset resolves the
        intervening steps.

- name: Chung-Jansen DNA Methylation Episignature
  description: >-
    Affected individuals carry a specific and sensitive genome-wide DNA methylation
    signature detectable on Infinium Methylation EPIC arrays. Two things make this
    more than a diagnostic convenience. First, it is direct patient-level (not
    cell-line) evidence that PHIP haploinsufficiency perturbs the epigenome, which is
    the prediction of the chromatin-reader model. Second, the CHUJANS signature
    partially overlaps those of White-Kernohan syndrome (DDB1 - the very CRL4 adaptor
    that PHIP docks onto) and Borjeson-Forssman-Lehmann syndrome (PHF6, another
    chromatin-associated NDD protein), so the shared episignature independently
    recovers the functional relationship rather than merely the clinical resemblance.
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  evidence:
  - reference: PMID:38787418
    reference_title: "The detection of a strong episignature for Chung-Jansen syndrome, partially overlapping with Borjeson-Forssman-Lehmann and White-Kernohan syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We assessed the DNAm profiles of affected individuals with pathogenic and
      likely pathogenic PHIP variants with Infinium Methylation EPIC arrays and
      report a specific and sensitive DNAm episignature biomarker for Chung-Jansen
      syndrome.
    explanation: >-
      Establishes the existence and diagnostic character of the episignature in
      patients.
  - reference: PMID:38787418
    reference_title: "The detection of a strong episignature for Chung-Jansen syndrome, partially overlapping with Borjeson-Forssman-Lehmann and White-Kernohan syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we observed similarities between the methylation profile of Chung-Jansen
      syndrome and that of functionally related and clinically partially overlapping
      genetic disorders, White-Kernohan syndrome (caused by variants in DDB1 gene)
      and Börjeson-Forssman-Lehmann syndrome (caused by variants in PHF6 gene)
    explanation: >-
      The cross-disorder overlap with DDB1 and PHF6 disorders is the evidence that
      the signature reflects shared chromatin-machinery pathophysiology.

- name: Replication Fork Destabilization Under Replication Stress
  description: >-
    A mechanistically separate consequence of PHIP/DCAF14 loss. Two CHUJANS missense
    variants located in different functional elements of DCAF14 - one in the WD40
    repeat domain, one in the pleckstrin-homology-binding region - both cause
    defective replication fork progression under replication stress and both fail to
    complete DNA replication after genotoxic exposure, implicating DCAF14 in the
    protection of stalled forks. The authors accordingly predict
    replication-associated genome instability in CHUJANS. Note that this is a
    prediction: no clinical instability phenotype (cancer predisposition, chromosome
    breakage) has been demonstrated in CHUJANS patients, so this node is modelled as
    a cellular defect without a curated clinical consequence.
  biological_scale: CELLULAR
  mechanism_confidence: HYPOTHETICAL
  biological_processes:
  - preferred_term: replication fork processing
    term:
      id: GO:0031297
      label: replication fork processing
    modifier: ABNORMAL
  evidence:
  - reference: PMID:35863899
    reference_title: "PHIP variants associated with Chung-Jansen syndrome disrupt replication fork stability and genome integrity."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      The variants p.D488V and p.E963G occur in different functional elements of
      DCAF14- WD40 repeat domain and pleckstrin homology-binding region (PBR),
      respectively.
    explanation: >-
      Identifies the two patient alleles tested and their domain locations.
  - reference: PMID:35863899
    reference_title: "PHIP variants associated with Chung-Jansen syndrome disrupt replication fork stability and genome integrity."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Furthermore, unlike wild type DCAF14, both variants fail to accomplish DNA
      replication after exposure to genotoxic stress indicating a critical role of
      DCAF14 in protecting stalled replication forks.
    explanation: >-
      Demonstrates the stalled-fork protection defect for both patient variants.
  - reference: PMID:35863899
    reference_title: "PHIP variants associated with Chung-Jansen syndrome disrupt replication fork stability and genome integrity."
    supports: PARTIAL
    evidence_source: IN_VITRO
    snippet: >-
      Thus, we have identified replication defects associated with CJS variants and
      predict replication-associated genome instability with CJS syndrome.
    explanation: >-
      The genome-instability consequence in patients is explicitly framed by the
      authors as a prediction, which is why this node is HYPOTHETICAL and has no
      curated clinical downstream.

- name: Repressed POMC Transcription
  description: >-
    PHIP has nuclear and cytoplasmic pools, and it is the nuclear pool that acts on
    POMC. Nuclear PHIP directly enhances transcription of pro-opiomelanocortin, the
    precursor from which the anorexigenic melanocortin peptides are cleaved, and
    obesity-associated PHIP variants repress that transcription. The physiological
    setting is the hypothalamic arcuate POMC neuron, the first-order anorexigenic
    node of the leptin-melanocortin pathway; the experimental demonstration, however,
    was in cells rather than in human hypothalamic neurons, which is the principal
    limitation of this arm.
  biological_scale: MOLECULAR
  mechanism_confidence: PROVISIONAL
  cell_types:
  - preferred_term: hypothalamic POMC (anorexigenic) neuron
    term:
      id: CL:4042033
      label: pro-opiomelanocortin neuron
  locations:
  - preferred_term: arcuate nucleus of the hypothalamus
    term:
      id: UBERON:0001932
      label: arcuate nucleus of hypothalamus
  biological_processes:
  - preferred_term: positive regulation of POMC transcription by RNA polymerase II
    term:
      id: GO:0045944
      label: positive regulation of transcription by RNA polymerase II
    modifier: DECREASED
  evidence:
  - reference: PMID:32492392
    reference_title: "Exome Sequencing Identifies Genes and Gene Sets Contributing to Severe Childhood Obesity, Linking PHIP Variants to Repressed POMC Transcription."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      In cells, we found that nuclear PHIP (pleckstrin homology domain interacting
      protein) directly enhances transcription of pro-opiomelanocortin (POMC), a
      neuropeptide that suppresses appetite.
    explanation: >-
      Establishes nuclear PHIP as a direct positive regulator of POMC transcription
      and names the anorexigenic function of the product.
  - reference: PMID:34773373
    reference_title: "PHIP gene variants with protein modeling, interactions, and clinical phenotypes."
    supports: PARTIAL
    evidence_source: COMPUTATIONAL
    snippet: >-
      Protein-protein interactions indicate involvement of POMC and related proteins
      with potential contribution to obesity, congenital, neuromuscular, and lipid
      disorders
    explanation: >-
      Independent in silico interaction analysis recovers the PHIP-POMC relationship;
      PARTIAL because it is predictive rather than experimental.
  downstream:
  - target: Impaired Central Melanocortin Satiety Signaling
    causal_link_type: DIRECT
    hypothesis_groups:
    - pomc_melanocortin_repression
    evidence:
    - reference: PMID:32492392
      reference_title: "Exome Sequencing Identifies Genes and Gene Sets Contributing to Severe Childhood Obesity, Linking PHIP Variants to Repressed POMC Transcription."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Our demonstration that PHIP is involved in human energy homeostasis through
        transcriptional regulation of central melanocortin signaling
      explanation: >-
        The authors' own framing of the downstream step from POMC transcription to
        central melanocortin signaling.

- name: Impaired Central Melanocortin Satiety Signaling
  description: >-
    Reduced POMC-derived melanocortin tone weakens the central satiety signal
    downstream of leptin, biasing energy balance toward positive. Clinically this
    manifests as overweight or obesity that is not usually present at birth but
    emerges between early childhood and puberty and becomes more prevalent with age -
    so a normal weight in a young child does not exclude the diagnosis or predict a
    normal adult weight.
  biological_scale: ORGANISM
  mechanism_confidence: PROVISIONAL
  locations:
  - preferred_term: hypothalamus
    term:
      id: UBERON:0001898
      label: hypothalamus
  biological_processes:
  - preferred_term: regulation of feeding behavior
    term:
      id: GO:0060259
      label: regulation of feeding behavior
    modifier: ABNORMAL
  - preferred_term: energy homeostasis
    term:
      id: GO:0097009
      label: energy homeostasis
    modifier: ABNORMAL
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The percentage of obese individuals was greater in the older age group (>12
      years old) and evolves over time.
    explanation: >-
      Documents the age-dependent emergence of the weight phenotype at the clinical
      level; PARTIAL because it evidences the downstream weight outcome rather than
      melanocortin signaling itself.
  downstream:
  - target: Obesity and Overweight
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    hypothesis_groups:
    - pomc_melanocortin_repression
    evidence:
    - reference: PMID:32492392
      reference_title: "Exome Sequencing Identifies Genes and Gene Sets Contributing to Severe Childhood Obesity, Linking PHIP Variants to Repressed POMC Transcription."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Using exome and targeted sequencing in 2,737 severely obese cases and 6,704
        controls, we identified three genes (PHIP, DGKI, and ZMYM4) with an excess
        burden of very rare predicted deleterious variants in cases.
      explanation: >-
        Human-genetic evidence that rare deleterious PHIP variants are enriched in
        severe obesity, connecting the pathway to the clinical outcome.

- name: Disrupted Neurodevelopmental Gene Expression Program
  description: >-
    The route from chromatin-reading failure to the neurodevelopmental phenotype is
    the least resolved segment of the CHUJANS pathograph. PHIP's isoforms are
    implicated in neurodevelopmental processes including neuronal differentiation,
    and the clinical output (global developmental delay, learning disability or
    intellectual disability, speech delay, hypotonia, and a behavioral/psychiatric
    profile) is highly consistent across cohorts. What is missing is any
    CHUJANS-specific patient-neuron, organoid, or brain transcriptomic dataset
    identifying the mis-regulated target genes, so the node is curated as a named but
    mechanistically unresolved intermediate rather than as an established pathway.
  biological_scale: CELLULAR
  mechanism_confidence: HYPOTHETICAL
  cell_types:
  - preferred_term: neuron
    term:
      id: CL:0000540
      label: neuron
  locations:
  - preferred_term: brain
    term:
      id: UBERON:0000955
      label: brain
  biological_processes:
  - preferred_term: nervous system development
    term:
      id: GO:0007399
      label: nervous system development
    modifier: ABNORMAL
  - preferred_term: neuron differentiation
    term:
      id: GO:0030182
      label: neuron differentiation
    modifier: ABNORMAL
  evidence:
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PHIP encodes two protein-isoforms, PHIP/DCAF14 and NDRP, each involved in
      neurodevelopmental processes, including E3 ubiquitination and neuronal
      differentiation
    explanation: >-
      Attributes neurodevelopmental roles including neuronal differentiation to the
      PHIP products; PARTIAL because the specific dysregulated program is unknown.
  downstream:
  - target: Global Developmental Delay
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:36726590
      reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        almost all individuals reported here show developmental delay (22/23)
      explanation: >-
        Developmental delay is near-universal in variant-confirmed individuals.
  - target: Intellectual Disability
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:36726590
      reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        learning disability or ID (22/23)
      explanation: >-
        Learning disability or intellectual disability is likewise near-universal.
  - target: Behavioral and Psychiatric Problems
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:36726590
      reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        behavioral abnormalities (20/23)
      explanation: >-
        Behavioral abnormality is one of the four defining components of the syndrome.
  - target: Hypotonia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:37961033
      reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Other common symptoms were hypotonia (78.7%)
      explanation: >-
        Hypotonia is present in the large majority of the natural-history cohort.
  - target: Craniofacial Dysmorphism
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:36726590
      reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        characteristic craniofacial features (i.e. large ears/earlobes, prominent
        eyebrows, anteverted nares and long philtrum (23/23))
      explanation: >-
        The facial gestalt was present in every individual in the European cohort.

- name: Disrupted PHIP-Dependent Kidney and Urinary Tract Development
  description: >-
    A distinct developmental arm outside the CNS. Prenatal expression studies in
    murine and human renal tissue support a role for PHIP in normal kidney and
    urinary tract development, and systematic ascertainment across CHUJANS and CAKUT
    cohorts recovered a urorenogenital trait in a substantial minority of individuals.
    The trait is variably expressive, which is why urorenal anomalies were missed in
    the original delineation and why the recommendation is now bidirectional:
    evaluate CHUJANS patients for urorenogenital malformation, and consider PHIP in
    syndromic CAKUT.
  biological_scale: TISSUE
  mechanism_confidence: PROVISIONAL
  locations:
  - preferred_term: kidney
    term:
      id: UBERON:0002113
      label: kidney
  biological_processes:
  - preferred_term: kidney development
    term:
      id: GO:0001822
      label: kidney development
    modifier: ABNORMAL
  evidence:
  - reference: PMID:39156152
    reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      The prenatal expression studies supported a role for PHIP in normal kidney and
      urinary tract development.
    explanation: >-
      The result, not the stated aim, of the prenatal expression work. Tagged
      MODEL_ORGANISM because the in vivo arm is murine; the same study profiled human
      fetal renal tissue ex vivo, and the human clinical arm is captured by the
      paired item below.
  - reference: PMID:39156152
    reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We identified 4 novel and 8 published cases, indicating variable expressivity
      with a urorenogenital trait frequency of 5% to 35%.
    explanation: >-
      Quantifies the human clinical frequency range of the urorenogenital trait.
  downstream:
  - target: Congenital Anomalies of the Kidney and Urinary Tract
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39156152
      reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Pathogenic PHIP gene variants should be considered as causative in patients
        with syndromal CAKUT.
      explanation: >-
        The authors' conclusion that PHIP loss is causative for the CAKUT phenotype.

phenotypes:
- category: Neurologic
  name: Global Developmental Delay
  frequency: VERY_FREQUENT
  description: >-
    Delayed attainment of motor, speech, and cognitive milestones, recognized in
    infancy or early childhood and present in essentially all variant-confirmed
    individuals. It is usually the presenting concern that triggers genetic testing.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      almost all individuals reported here show developmental delay (22/23)
    explanation: >-
      22/23 (96%) supports the VERY_FREQUENT band (80-100%).
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Remarkably, all 23 individuals had developmental delay/ID and the majority were
      overweight or obese.
    explanation: >-
      An independent cohort in which developmental delay/ID was universal.

- category: Neurologic
  name: Intellectual Disability
  frequency: VERY_FREQUENT
  description: >-
    Learning disability or intellectual disability, typically mild to moderate but
    ranging to moderate-severe. Adaptive functioning measured on the Vineland-3 in
    the largest cohort was moderately low rather than profoundly impaired, consistent
    with the observation that some carrier parents are only mildly affected.
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      learning disability or ID (22/23)
    explanation: >-
      22/23 (96%) supports the VERY_FREQUENT band.
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Most individuals had moderately low adaptive functioning based on the
      Vineland-3 (mean = 76.8, standard deviation = 12.0).
    explanation: >-
      Quantifies the severity as moderately low adaptive functioning rather than
      severe impairment.
  - reference: PMID:42355777
    reference_title: "Chung-Jansen Syndrome in a Young Woman with a PHIP Variant: Severe Obesity, Intellectual Disability, and Endocrine Abnormalities."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      moderate-to-severe intellectual disability (full-scale IQ 38)
    explanation: >-
      Documents the severe end of the cognitive range; PARTIAL because it is a single
      case and does not represent the cohort-typical mild-to-moderate severity.

- category: Neurologic
  name: Delayed Speech and Language Development
  description: >-
    Delayed speech and language acquisition is a recurrent early feature and one of
    the principal targets for early intervention. It is reported consistently across
    case reports and cohorts but has not been given a single cohort-wide denominator,
    so no frequency band is asserted.
  phenotype_term:
    preferred_term: Delayed speech and language development
    term:
      id: HP:0000750
      label: Delayed speech and language development
  evidence:
  - reference: PMID:41383545
    reference_title: "Comorbidity of Attention Deficit Hyperactivity Disorder (ADHD) and Chung-Jansen Syndrome: Case Report and Review of Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Although clinical presentations vary, behavioral problems and delayed motor and
      speech milestones are common.
    explanation: >-
      A literature review characterizing delayed speech milestones as a common
      feature.

- category: Neurologic
  name: Hypotonia
  frequency: FREQUENT
  description: >-
    Generalized low muscle tone, often noted in infancy alongside feeding difficulty
    and contributing to motor delay and impaired balance. It is one of the most
    frequent non-cognitive features in the largest cohort.
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Other common symptoms were hypotonia (78.7%)
    explanation: >-
      78.7% falls in the FREQUENT band (30-79%), just below the VERY_FREQUENT
      threshold.
  - reference: PMID:27900362
    reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      common clinical features of developmental delay, intellectual disability,
      anxiety, hypotonia, poor balance, obesity, and dysmorphic features
    explanation: >-
      Hypotonia was among the shared features in the founding report.

- category: Neurologic
  name: Impaired Balance and Coordination
  description: >-
    Poor balance and coordination, plausibly downstream of hypotonia, was among the
    features shared by the first reported patients. It remains incompletely
    quantified across cohorts, so no frequency band is asserted.
  phenotype_term:
    preferred_term: Incoordination
    term:
      id: HP:0002311
      label: Incoordination
  evidence:
  - reference: PMID:27900362
    reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      common clinical features of developmental delay, intellectual disability,
      anxiety, hypotonia, poor balance, obesity, and dysmorphic features
    explanation: >-
      Poor balance is explicitly listed among the shared clinical features.

- category: Behavioral
  name: Behavioral and Psychiatric Problems
  frequency: VERY_FREQUENT
  description: >-
    Behavioral abnormality is one of the four cardinal components of the syndrome.
    The reported repertoire includes hyperactivity, impulsivity, aggression, autistic
    features, anxiety, and mood disorder. In natural-history data the psychiatric
    burden is not static: depression becomes significantly more common after age 12,
    which is the basis for the recommendation to maintain behavioral-health
    surveillance into adolescence and adulthood.
  phenotype_term:
    preferred_term: Behavioral abnormality
    term:
      id: HP:0000708
      label: Atypical behavior
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      behavioral abnormalities (20/23)
    explanation: >-
      20/23 (87%) supports the VERY_FREQUENT band. The band is deliberately bound to
      the aggregate behavioral-abnormality term, because no single named behavior
      reaches this frequency - see the separate ADHD, anxiety, depression, autistic
      behavior and aggression entries for the component rates.
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Other features comprised behavioral problems (hyperactivity, aggression,
      features of autism and/or mood disorder)
    explanation: >-
      Enumerates the behavioral repertoire including aggression, the bound HPO term.

- category: Behavioral
  name: Aggressive Behavior
  frequency: OCCASIONAL
  description: >-
    Aggression is part of the behavioral repertoire but is emphatically not the
    dominant one, and it is much less frequent than the aggregate behavioral-problem
    figure. This distinction matters clinically because aggression is the feature
    most often used to contrast CHUJANS with CUL4B-related Cabezas syndrome, where
    aggressive outbursts are far more common.
  phenotype_term:
    preferred_term: Aggressive behavior
    term:
      id: HP:0000718
      label: Aggressive behavior
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This feature has also been reported in our cohort but only in 6/23 individuals.
    explanation: >-
      6/23 (26%) supports the OCCASIONAL band (5-29%), well below the 87% aggregate
      behavioral-abnormality rate.
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Overall, 86.4% of our cohort show a kind of behavioral change, but aggressions
      seem not to be the most common one.
    explanation: >-
      The authors explicitly separate the high aggregate behavioral rate from the
      much lower aggression rate.

- category: Behavioral
  name: Attention Deficit Hyperactivity Disorder
  frequency: FREQUENT
  description: >-
    ADHD is the single most frequent named psychiatric diagnosis in the syndrome,
    affecting about half of individuals in the largest cohort, and is a specific
    treatment target.
  phenotype_term:
    preferred_term: Attention deficit hyperactivity disorder
    term:
      id: HP:0007018
      label: Attention deficit hyperactivity disorder
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      attention-deficit/hyperactivity disorder (51.1%)
    explanation: >-
      51.1% falls in the FREQUENT band (30-79%).
  - reference: PMID:41383545
    reference_title: "Comorbidity of Attention Deficit Hyperactivity Disorder (ADHD) and Chung-Jansen Syndrome: Case Report and Review of Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      It is characterized by developmental delay, intellectual disability, behavioral
      disturbances including autism spectrum disorder and attention deficit
      hyperactivity disorder, obesity, and distinct facial dysmorphism such as
      synophrys and an upturned nose.
    explanation: >-
      A dedicated case report and review confirming ADHD as a characteristic
      behavioral manifestation.

- category: Behavioral
  name: Anxiety
  frequency: FREQUENT
  description: >-
    Anxiety was present in the very first reported patients and affects nearly half
    of the largest cohort.
  phenotype_term:
    preferred_term: Anxiety
    term:
      id: HP:0000739
      label: Anxiety
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      anxiety (46.8%)
    explanation: >-
      46.8% falls in the FREQUENT band.
  - reference: PMID:27900362
    reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      two unrelated patients with common clinical features of developmental delay,
      intellectual disability, anxiety, hypotonia, poor balance, obesity, and
      dysmorphic features
    explanation: >-
      Anxiety was one of the shared features in the founding two-patient report.

- category: Behavioral
  name: Depression
  frequency: OCCASIONAL
  description: >-
    Depression is less frequent than anxiety overall but is strongly age-dependent -
    significantly more common in individuals older than 12 years - making it the
    clearest example of the syndrome's evolving psychiatric profile and the main
    argument for lifelong rather than paediatric-only mental-health follow-up.
  phenotype_term:
    preferred_term: Depression
    term:
      id: HP:0000716
      label: Depression
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      depression (27.7%)
    explanation: >-
      27.7% falls in the OCCASIONAL band (5-29%).
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Depression was significantly higher in the older age group (>12 years old).
    explanation: >-
      Establishes the age dependence that motivates ongoing surveillance.

- category: Behavioral
  name: Autistic Behavior
  description: >-
    Autistic features are part of the behavioral repertoire and were reported from
    the earliest cohorts onward, though without a consistent cohort-wide denominator.
  phenotype_term:
    preferred_term: Autistic behavior
    term:
      id: HP:0000729
      label: Autistic behavior
  evidence:
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      behavioral problems (hyperactivity, aggression, features of autism and/or mood
      disorder)
    explanation: >-
      Features of autism are listed among the behavioral problems.

- category: Neurologic
  name: Sleep Disturbance
  frequency: FREQUENT
  description: >-
    Sleep difficulties affect over 40% of individuals. Recent work distinguishes two
    contributors that should not be conflated: behavioral/neurodevelopmental sleep
    problems, and true sleep-disordered breathing driven by obesity, which requires
    polysomnography to identify.
  phenotype_term:
    preferred_term: Sleep disturbance
    term:
      id: HP:0002360
      label: Sleep disturbance
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      sleep difficulties (42.6%)
    explanation: >-
      42.6% falls in the FREQUENT band.

- category: Neurologic
  name: Seizure
  frequency: OCCASIONAL
  description: >-
    Seizures are a real but minority feature and are not part of the syndrome's
    defining core. Reported types include complex partial (focal impaired awareness),
    suspected generalized tonic-clonic, and febrile seizures; EEG may be normal.
    Cohort rates differ with ascertainment, and the conservative band follows the
    larger European series rather than the smaller clinic-based one.
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Seizures (17.39%)
    explanation: >-
      17.39% in the 23-individual European cohort falls in the OCCASIONAL band
      (5-29%).
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Seizure or suspected seizure activity were observed in four individuals.
    explanation: >-
      4/10 in a smaller clinic-ascertained series, higher than the European cohort;
      PARTIAL because it argues for a rate above the assigned band and the two
      denominators are not reconciled.

- category: Respiratory
  name: Obstructive Sleep Apnea
  description: >-
    Obstructive sleep apnea has now been confirmed polysomnographically in
    Chung-Jansen syndrome for the first time, in an adult with intellectual
    disability in whom severe REM-predominant OSA prompted the syndromic workup that
    made the molecular diagnosis. Because sleep complaints are frequent but had never
    been objectively characterized, the reported case supports proactive OSA
    screening, particularly in individuals with obesity. No frequency band is
    asserted - this is a single case, not a prevalence estimate.
  phenotype_term:
    preferred_term: Obstructive sleep apnea
    term:
      id: HP:0002870
      label: Obstructive sleep apnea
    severity: SEVERE
  evidence:
  - reference: PMID:41751879
    reference_title: "Sleep-Disordered Breathing in Chung-Jansen Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Overnight polysomnography revealed a severe rapid eye movement-predominant
      obstructive sleep apnea syndrome with an apnea-hypopnea index of 31.9 events
      per hour
    explanation: >-
      Objective polysomnographic documentation of severe OSA in a molecularly
      confirmed patient.
  - reference: PMID:41751879
    reference_title: "Sleep-Disordered Breathing in Chung-Jansen Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This adult case provides the first polysomnographic confirmation in the
      syndrome, supporting proactive screening for obstructive sleep apnea-especially
      in those with obesity.
    explanation: >-
      Establishes both the novelty of the objective confirmation and the resulting
      screening recommendation.

- category: Metabolic
  name: Obesity and Overweight
  frequency: FREQUENT
  description: >-
    Overweight or obesity affects a slight majority of individuals and is the feature
    that gave the syndrome its historical acronyms (DIDOD, BIDOD, ID-overweight
    syndrome). Crucially it is neither congenital nor obligatory: it emerges between
    early childhood and puberty, becomes more prevalent in the over-12 age group, and
    is absent in a sizeable minority - one independent cohort explicitly reported a
    lower obesity frequency than earlier series. Weight should therefore not be used
    as a gatekeeping criterion for testing.
  phenotype_term:
    preferred_term: Obesity
    term:
      id: HP:0001513
      label: Obesity
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Overall, 55.8% of individuals were obese/overweight.
    explanation: >-
      55.8% falls in the FREQUENT band (30-79%).
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      weight problems (13/23)
    explanation: >-
      13/23 (57%) in an independent European cohort, concordant with the FREQUENT
      band.
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The additional individuals we report have a lower frequency of obesity than
      previous reports and a higher frequency of gastrointestinal problems, social
      deficits, and behavioral challenges.
    explanation: >-
      Documents the incomplete penetrance of obesity; PARTIAL because it qualifies
      rather than supports a high frequency.
  - reference: PMID:33867250
    reference_title: "Chung-Jansen Syndrome with obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Chung-Jansen Syndrome is a recently identified obesity syndrome, characteristic
      clinical features of which are global developmental delay, intellectual
      disability, obesity and dysmorphism (DIDOD).
    explanation: >-
      Frames the disorder as a syndromic obesity and gives the DIDOD acronym.

- category: Craniofacial
  name: Craniofacial Dysmorphism
  frequency: VERY_FREQUENT
  description: >-
    A recognizable facial gestalt comprising large ears and earlobes, prominent
    eyebrows (often with synophrys), anteverted nares/upturned nose, and a long
    philtrum. It was present in every individual in the European cohort. Objective
    facial phenotyping with GestaltMatcher separates PHIP patients from healthy
    controls and from Prader-Willi and CUL4B-related syndromes, but cannot separate
    PHIP variant classes from one another - so the gestalt supports recognition, not
    genotype prediction, and never substitutes for molecular testing.
  phenotype_term:
    preferred_term: Characteristic facial gestalt
    term:
      id: HP:0001999
      label: Abnormal facial shape
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      characteristic craniofacial features (i.e. large ears/earlobes, prominent
      eyebrows, anteverted nares and long philtrum (23/23))
    explanation: >-
      23/23 (100%) supports the VERY_FREQUENT band. Note that the 100% denominator is
      for the aggregate gestalt, which is why this band is bound to the aggregate
      facial-shape term; the individual components are each far less frequent and
      carry their own, lower bands below.
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we could establish that PHIP patients are indistinguishable based on the type
      of PHIP alteration (e.g. missense, loss-of-function, splice site) but show a
      significant difference to the average face of healthy individuals as well as to
      individuals with Prader-Willi syndrome (PWS, OMIM #176270) or with a
      CUL4B-alteration
    explanation: >-
      Quantifies both the discriminative power of the gestalt against key
      differentials and its inability to predict variant class.

- category: Craniofacial
  name: Macrotia
  frequency: FREQUENT
  description: >-
    Large ears and prominent earlobes, the joint most frequent single component of
    the facial gestalt.
  phenotype_term:
    preferred_term: Macrotia
    term:
      id: HP:0000400
      label: Macrotia
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the most common features are large ears/earlobes (61%) and prominent eyebrows
      (61%), followed by anteverted nares (52%)
    explanation: >-
      61% falls in the FREQUENT band (30-79%), not VERY_FREQUENT - the per-feature
      rate is well below the 100% aggregate-gestalt rate.
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The most common facial features were thick helices and earlobes/larger ears
      (8/10)
    explanation: >-
      An independent cohort in which large ears/earlobes were also the most frequent
      facial feature.

- category: Craniofacial
  name: Synophrys
  description: >-
    Confluent eyebrows across the glabella. Together with the prominent/full eyebrows
    this is the single facial feature that most drives the clinical confusion with
    Cornelia de Lange syndrome.
  phenotype_term:
    preferred_term: Synophrys
    term:
      id: HP:0000664
      label: Synophrys
  evidence:
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      dysmorphisms (full eyebrows and/or synophrys, upturned nose, large ears and
      tapering fingers)
    explanation: >-
      Synophrys is explicitly listed among the syndrome's dysmorphic features.

- category: Craniofacial
  name: Thick Eyebrow
  frequency: FREQUENT
  description: >-
    Full or prominent eyebrows, reported in both the delineating cohorts and the
    joint most frequent single component of the facial gestalt.
  phenotype_term:
    preferred_term: Thick eyebrow
    term:
      id: HP:0000574
      label: Thick eyebrow
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the most common features are large ears/earlobes (61%) and prominent eyebrows
      (61%), followed by anteverted nares (52%)
    explanation: >-
      61% falls in the FREQUENT band; the aggregate-gestalt 100% figure does not
      apply to this individual feature.

- category: Craniofacial
  name: Anteverted Nares
  frequency: FREQUENT
  description: >-
    Upturned nose with anteverted nostrils, the third most frequent component of the
    facial gestalt.
  phenotype_term:
    preferred_term: Anteverted nares
    term:
      id: HP:0000463
      label: Anteverted nares
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the most common features are large ears/earlobes (61%) and prominent eyebrows
      (61%), followed by anteverted nares (52%)
    explanation: >-
      52% falls in the FREQUENT band.

- category: Craniofacial
  name: Long Philtrum
  frequency: FREQUENT
  description: >-
    An elongated philtrum. Although it is one of the four named gestalt components,
    it is the least frequent of them and is present in well under half of
    individuals - so its absence does not argue against the diagnosis.
  phenotype_term:
    preferred_term: Long philtrum
    term:
      id: HP:0000343
      label: Long philtrum
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Less frequent dysmorphism comprise a long philtrum (30%)
    explanation: >-
      30% sits at the bottom of the FREQUENT band (30-79%), far below the aggregate
      gestalt rate.

- category: Skeletal
  name: Tapered Fingers
  description: >-
    Digits tapering distally, listed among the dysmorphic features in the
    syndrome-delineating cohort.
  phenotype_term:
    preferred_term: Tapered finger
    term:
      id: HP:0001182
      label: Tapered finger
  evidence:
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      dysmorphisms (full eyebrows and/or synophrys, upturned nose, large ears and
      tapering fingers)
    explanation: >-
      Tapering fingers are explicitly listed among the dysmorphic features.

- category: Skeletal
  name: Brachydactyly
  frequency: FREQUENT
  description: >-
    Short digits, present in a substantial minority of the European cohort and also
    reported as brachydactyly type E1 in an independent adult case.
  phenotype_term:
    preferred_term: Brachydactyly
    term:
      id: HP:0001156
      label: Brachydactyly
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      30% of the individuals showed brachydactyly
    explanation: >-
      30% is the lower bound of the FREQUENT band (30-79%), the same figure and
      therefore the same band as the long philtrum from this cohort.

- category: Skeletal
  name: Clinodactyly of the 5th Finger
  frequency: FREQUENT
  description: >-
    Inward curvature of the fifth finger, reported at similar rates in two
    independent series.
  phenotype_term:
    preferred_term: Clinodactyly of the 5th finger
    term:
      id: HP:0004209
      label: Clinodactyly of the 5th finger
  evidence:
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Other features included clinodactyly of the fifth finger (5/10)
    explanation: >-
      5/10 (50%) falls in the FREQUENT band.

- category: Skeletal
  name: Toe Syndactyly
  frequency: OCCASIONAL
  description: >-
    Cutaneous syndactyly of the second and third toes, a minor but recurrent limb
    finding in both delineating series.
  phenotype_term:
    preferred_term: 2-3 toe syndactyly
    term:
      id: HP:0004691
      label: 2-3 toe syndactyly
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      26% of the individuals showed syndactyly of the second/third toes.
    explanation: >-
      26% falls in the OCCASIONAL band (5-29%).

- category: Gastrointestinal
  name: Constipation
  frequency: FREQUENT
  description: >-
    Constipation affects roughly half of individuals; gastrointestinal problems more
    broadly were flagged as more frequent than initially appreciated in one
    independent cohort.
  phenotype_term:
    preferred_term: Constipation
    term:
      id: HP:0002019
      label: Constipation
    temporality: CHRONIC
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      constipation (48.9%)
    explanation: >-
      48.9% falls in the FREQUENT band.
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      a higher frequency of gastrointestinal problems, social deficits, and
      behavioral challenges
    explanation: >-
      Independent cohort emphasizing gastrointestinal involvement.

- category: Gastrointestinal
  name: Gastroesophageal Reflux
  frequency: FREQUENT
  description: >-
    Reflux is the second gastrointestinal manifestation after constipation and can be
    severe; in one reported infant, reflux together with feeding difficulty required
    continued nasogastric feeding well into the second year.
  phenotype_term:
    preferred_term: Gastroesophageal reflux
    term:
      id: HP:0002020
      label: Gastroesophageal reflux
  evidence:
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Gastrointestinal problems were also commonly reported, primarily chronic
      constipation (7/10) and gastroesophageal reflux disease (GERD) (4/10).
    explanation: >-
      4/10 (40%) falls in the FREQUENT band.

- category: Gastrointestinal
  name: Feeding Difficulties
  frequency: FREQUENT
  description: >-
    Neonatal and infantile feeding difficulty is the most commonly reported early
    problem, typically alongside hypotonia, and is one of the first management
    demands the syndrome makes.
  phenotype_term:
    preferred_term: Feeding difficulties
    term:
      id: HP:0011968
      label: Feeding difficulties
  evidence:
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Feeding difficulties (7/10), hypotonia (4/10), and neonatal jaundice (3/10)
      were the most commonly reported neonatal issues.
    explanation: >-
      7/10 (70%) falls in the FREQUENT band and identifies feeding difficulty as the
      leading neonatal issue.

- category: Ophthalmologic
  name: Visual Impairment
  frequency: FREQUENT
  description: >-
    Visual problems affect about two-thirds of individuals in the largest cohort,
    which is high enough that formal ophthalmological assessment is warranted rather
    than symptom-triggered referral. The cohort reports the aggregate category rather
    than a breakdown by refractive error, strabismus, or cortical visual impairment.
  phenotype_term:
    preferred_term: Visual impairment
    term:
      id: HP:0000505
      label: Visual impairment
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      visual problems (66%)
    explanation: >-
      66% falls in the FREQUENT band.
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      ophthalmologic problems were common (8/10); most commonly amblyopia (4/10) and
      also myopia, astigmatism, and convergence disorder.
    explanation: >-
      An independent cohort giving both a concordant aggregate rate and the
      breakdown the larger cohort omits - amblyopia predominating, which is the
      finding that makes early ophthalmological referral time-critical.

- category: Genitourinary
  name: Cryptorchidism
  frequency: FREQUENT
  description: >-
    Undescended testis affects a substantial minority of affected males. Genital
    malformation was recognized in CHUJANS before the broader urorenal association
    was systematically established.
  phenotype_term:
    preferred_term: Cryptorchidism
    term:
      id: HP:0000028
      label: Cryptorchidism
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      cryptorchidism (39.1% of males)
    explanation: >-
      39.1% of males falls in the FREQUENT band; note the denominator is males only.

- category: Genitourinary
  name: Congenital Anomalies of the Kidney and Urinary Tract
  frequency: OCCASIONAL
  description: >-
    Urorenogenital malformation is a genuine but variably expressive part of the
    CHUJANS spectrum, recovered only when CHUJANS and CAKUT cohorts were
    cross-interrogated. Reported anomalies include hypoplastic kidney. The reported
    frequency range (5-35%) is wide because ascertainment differs sharply between
    neurodevelopmental and nephrology cohorts; the conservative OCCASIONAL band is
    assigned on the lower, neurodevelopmental-cohort end. The bound term is the
    urinary-system abnormality rather than a renal-morphology term, because CAKUT and
    the source's "urorenogenital trait" both span the collecting system and not only
    the kidney; the genital component of that trait is curated separately as
    cryptorchidism.
  phenotype_term:
    preferred_term: Congenital anomaly of the kidney and urinary tract
    term:
      id: HP:0000079
      label: Abnormality of the urinary system
  evidence:
  - reference: PMID:39156152
    reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We identified 4 novel and 8 published cases, indicating variable expressivity
      with a urorenogenital trait frequency of 5% to 35%.
    explanation: >-
      Gives the reported frequency range; the low end (5%) sits in the OCCASIONAL
      band and is used conservatively.
  - reference: PMID:39156152
    reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Conversely, patients with CHUJANS should be clinically evaluated for
      urorenogenital manifestations.
    explanation: >-
      Establishes the clinical-surveillance implication of the association.
  - reference: PMID:33867250
    reference_title: "Chung-Jansen Syndrome with obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We present a child with the syndrome who also had hypothyroidism and renal
      involvement in form of small kidneys on one side.
    explanation: >-
      An independent case with unilateral small kidney, an example of the renal
      anomaly spectrum.

- category: Endocrine
  name: Hypothyroidism
  description: >-
    Hypothyroidism has been documented in at least two independent CHUJANS patients,
    including one with subclinical primary hypothyroidism of autoimmune origin. It is
    not established as a core feature and no cohort frequency exists, but it is
    treatable and cheap to look for, which is the argument for including thyroid
    function in the endocrine workup.
  phenotype_term:
    preferred_term: Hypothyroidism
    term:
      id: HP:0000821
      label: Hypothyroidism
  evidence:
  - reference: PMID:33867250
    reference_title: "Chung-Jansen Syndrome with obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We present a child with the syndrome who also had hypothyroidism and renal
      involvement in form of small kidneys on one side.
    explanation: >-
      Documents hypothyroidism in a molecularly confirmed child.
  - reference: PMID:42355777
    reference_title: "Chung-Jansen Syndrome in a Young Woman with a PHIP Variant: Severe Obesity, Intellectual Disability, and Endocrine Abnormalities."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Laboratory investigations documented subclinical primary hypothyroidism of
      autoimmune origin
    explanation: >-
      An independent adult case with autoimmune subclinical primary hypothyroidism.

- category: Metabolic
  name: Impaired Glucose Tolerance with Hyperinsulinism
  description: >-
    Obesity-associated dysglycaemia. In the one CHUJANS patient given a systematic
    endocrine workup, impaired glucose tolerance with hyperinsulinism was found
    alongside severe obesity. Single-case evidence only; no frequency asserted.
  phenotype_term:
    preferred_term: Impaired glucose tolerance
    term:
      id: HP:0040270
      label: Impaired glucose tolerance
  evidence:
  - reference: PMID:42355777
    reference_title: "Chung-Jansen Syndrome in a Young Woman with a PHIP Variant: Severe Obesity, Intellectual Disability, and Endocrine Abnormalities."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      impaired glucose tolerance with associated hyperinsulinism
    explanation: >-
      Documents dysglycaemia with hyperinsulinism in a molecularly confirmed patient
      with severe obesity.

- category: Endocrine
  name: Oligomenorrhea
  description: >-
    Oligomenorrhoea was the presenting complaint in a young woman with severe obesity
    and CHUJANS, and was worked up as a polycystic-ovarian-type endocrine picture
    (reported as polyendocrine metabolic ovarian syndrome). The bound term is the
    menstrual finding actually documented rather than an ovarian-morphology term,
    since no ovarian morphology is reported. As with the other endocrine findings
    this rests on a single detailed workup and is curated to motivate
    reproductive-endocrine assessment, not as an established disease feature.
  phenotype_term:
    preferred_term: Oligomenorrhea
    term:
      id: HP:0000876
      label: Oligomenorrhea
  evidence:
  - reference: PMID:42355777
    reference_title: "Chung-Jansen Syndrome in a Young Woman with a PHIP Variant: Severe Obesity, Intellectual Disability, and Endocrine Abnormalities."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      referred to our centre for evaluation of oligomenorrhea in the context of
      severe obesity
    explanation: >-
      Documents oligomenorrhoea as the presenting endocrine complaint in a
      molecularly confirmed CHUJANS patient.
  - reference: PMID:42355777
    reference_title: "Chung-Jansen Syndrome in a Young Woman with a PHIP Variant: Severe Obesity, Intellectual Disability, and Endocrine Abnormalities."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      polyendocrine metabolic ovarian syndrome (PMOS, previously known as PCOS)
    explanation: >-
      The endocrine diagnosis reached; PARTIAL because the report does not state
      ovarian morphology, so no morphology term is bound.

prevalence:
- population: Worldwide
  measure_type: CASES_IN_LITERATURE
  prevalence_class: ULTRA_RARE
  notes: >-
    Cumulative published case counts rather than a population rate. No validated
    population prevalence or incidence figure exists for Chung-Jansen syndrome. A
    2022 systematic literature review counted 35 patients with unique
    protein-affecting PHIP variants; the 2022 European cohort added 23 individuals
    and the 2024 natural-history study reported 47, with partial overlap between
    series, so the reported total is on the order of one hundred individuals rather
    than a precisely enumerable figure. Orphanet has a record (ORPHA:589905) but no
    Orphadata prevalence row is available in this repository's cache and the
    Orphadata refresh is currently failing a manifest checksum, so no Orphanet
    epidemiology class is quoted. PHIP alterations are described as a rare cause of
    developmental delay / intellectual disability, and the disorder is regarded as
    underdiagnosed because mildly affected transmitting parents are frequently
    recognized only retrospectively.
  evidence:
  - reference: PMID:34773373
    reference_title: "PHIP gene variants with protein modeling, interactions, and clinical phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Following a systematic literature review, 35 patients are reported to have
      unique PHIP variants impacting the encoded protein product.
    explanation: >-
      Gives a cumulative published case count of 35 as of the 2022 review.
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report phenotypes and genotypes of 47 individuals with likely
      pathogenic/pathogenic PHIP variants.
    explanation: >-
      The largest single reported series, 47 individuals.
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      So far, PHIP alterations appear to be a rare cause of DD/ID.
    explanation: >-
      Directly supports the ULTRA_RARE qualitative band and the framing as a rare
      cause of DD/ID.

genetic:
- name: PHIP Pathogenic Variants
  gene_term:
    preferred_term: PHIP
    term:
      id: hgnc:15673
      label: PHIP
  association: Causative
  presence: Positive
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  notes: >-
    PHIP lies at 6q14.1. Reported pathogenic alleles are heterozygous and span
    nonsense, frameshift, splice-site, and missense substitutions plus intragenic,
    whole-gene, and contiguous deletions; the 2022 European cohort used NM_017934.7
    as the reference transcript. There is no mutational hotspot, and the facial
    gestalt does not discriminate variant class, so genotype-based prognostication is
    not currently possible. The locus produces more than one protein product
    (PHIP/DCAF14 and NDRP) and the genotype-phenotype evidence assigns causality to
    loss of PHIP/DCAF14. Contiguous deletions extending beyond PHIP can blend in
    features attributable to co-deleted neighbouring genes, and dual molecular
    diagnoses have been reported (one patient carried pathogenic variants in both
    PHIP and CLCN4), so an atypically severe presentation warrants looking beyond the
    PHIP allele rather than assuming expressivity.
  evidence:
  - reference: PMID:29209020
    reference_title: "A genotype-first approach identifies an intellectual disability-overweight syndrome caused by PHIP haploinsufficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Amongst these, PHIP was shown to have an enrichment of disruptive mutations in
      the individuals with ID (5 out of 3,275).
    explanation: >-
      The statistical gene-level enrichment in an intellectual-disability cohort that
      established PHIP as an ID gene.
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report an additional 10 individuals with pleckstrin homology
      domain-interacting protein (PHIP)-predicted deleterious variants (four
      frameshift, three missense, two nonsense, and one splice site; six of which are
      confirmed de novo).
    explanation: >-
      Enumerates the variant classes and the de novo proportion in an independent
      series.
  - reference: PMID:41383545
    reference_title: "Comorbidity of Attention Deficit Hyperactivity Disorder (ADHD) and Chung-Jansen Syndrome: Case Report and Review of Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Whole Exome Sequencing revealed pathogenic mutations in both the PHIP and CLCN4
      genes.
    explanation: >-
      Supports the dual-diagnosis caveat in the notes: an atypically severe
      presentation was explained by a second pathogenic locus, not by PHIP
      expressivity alone.

diagnosis:
- name: Trio exome or genome sequencing
  description: >-
    Diagnosis is molecular. The facial gestalt is suggestive but not pathognomonic,
    intellectual disability is often mild, and obesity is neither congenital nor
    obligatory, so CHUJANS is normally identified by trio exome or genome sequencing
    performed for developmental delay rather than by targeted testing. PHIP should be
    on neurodevelopmental and syndromic-obesity panels. Trio (rather than
    proband-only) testing matters disproportionately here because a meaningful
    minority of alleles are inherited from a parent whose own mild learning,
    behavioral, or weight phenotype is recognized only in retrospect.
  diagnosis_term:
    preferred_term: trio exome or genome sequencing
    term:
      id: NCIT:C101295
      label: Whole Exome Sequencing
  results: >-
    A heterozygous pathogenic or likely pathogenic PHIP variant establishes the
    diagnosis.
  evidence:
  - reference: PMID:27900362
    reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Using whole-exome sequencing, we have identified novel de novo heterozygous
      pleckstrin homology domain-interacting protein (PHIP) variants that are
      predicted to be deleterious
    explanation: >-
      Whole-exome sequencing is the route by which the founding cases were
      identified.
  - reference: PMID:39437749
    reference_title: "Novel Insights: A Novel PHIP Variant in a Family with Severe Early-Onset Obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Screening for PHIP variants should be included in genetic testing in patients
      with severe early-onset obesity.
    explanation: >-
      Supports including PHIP on syndromic-obesity testing as well as
      neurodevelopmental testing.

- name: Copy-number analysis by chromosomal microarray or exome CNV calling
  description: >-
    Sequence-level analysis alone will miss a real fraction of cases. Intragenic,
    whole-gene, and contiguous 6q14.1 deletions encompassing PHIP are an established
    route to the phenotype, and microdeletions including PHIP were part of the
    original evidence that the mechanism is loss of function. Copy-number analysis
    should therefore run in parallel with sequencing, with qPCR or FISH used to
    confirm a detected deletion and test parental segregation.
  diagnosis_term:
    preferred_term: chromosomal microarray analysis
    term:
      id: NCIT:C18477
      label: Microarray Analysis
  results: >-
    A heterozygous deletion involving PHIP establishes the diagnosis; a deletion
    extending well beyond PHIP predicts additional features from co-deleted genes.
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      technologies such as exome sequencing or array analyses have led to the
      identification of distinct types of alterations of PHIP
    explanation: >-
      Array analysis sits alongside exome sequencing as a primary detection method.
  - reference: PMID:27900362
    reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients with microdeletions of 6q14.1, including PHIP, have a similar
      phenotype of developmental delay, intellectual disability, hypotonia, and
      obesity
    explanation: >-
      Establishes deletions at 6q14.1 as a route to the same phenotype.

- name: DNA methylation episignature testing
  description: >-
    A specific and sensitive DNA methylation episignature for Chung-Jansen syndrome
    has been defined on Infinium Methylation EPIC arrays from patient blood. Its
    practical role is variant interpretation: it can reclassify PHIP variants of
    uncertain significance and can be deployed within a multiclass episignature
    classifier. Because the CHUJANS signature partially overlaps those of DDB1- and
    PHF6-related disorders, a combined signature for the three has also been
    developed, which means an episignature result should be read as evidence about
    this functional group rather than as a fully orthogonal single-gene test.
  diagnosis_term:
    preferred_term: DNA methylation episignature analysis
    term:
      id: NCIT:C63328
      label: DNA Methylation Analysis
  results: >-
    A positive Chung-Jansen episignature supports pathogenicity of a PHIP variant of
    uncertain significance.
  evidence:
  - reference: PMID:38787418
    reference_title: "The detection of a strong episignature for Chung-Jansen syndrome, partially overlapping with Borjeson-Forssman-Lehmann and White-Kernohan syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      These newly defined episignatures can be used as part of a multiclass
      episignature classifier for screening of affected individuals with rare
      disorders and interpretation of genetic variants of unknown clinical
      significance
    explanation: >-
      States the intended diagnostic application, VUS interpretation within a
      multiclass classifier.

- name: Polysomnography for suspected sleep-disordered breathing
  description: >-
    Sleep complaints are frequent in CHUJANS but had never been objectively
    characterized until an adult case underwent overnight polysomnography and was
    found to have severe REM-predominant obstructive sleep apnea. Polysomnography is
    therefore indicated when sleep-disordered breathing is suspected, particularly in
    individuals with obesity, rather than attributing all sleep problems to the
    behavioral phenotype.
  diagnosis_term:
    preferred_term: polysomnography
    term:
      id: NCIT:C114185
      label: Polysomnography
  results: >-
    An elevated apnea-hypopnea index establishes obstructive sleep apnea and
    indicates positive-airway-pressure therapy.
  evidence:
  - reference: PMID:41751879
    reference_title: "Sleep-Disordered Breathing in Chung-Jansen Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Despite frequent reports of sleep problems, systematic evaluation of
      sleep-disordered breathing has been limited.
    explanation: >-
      Identifies the diagnostic gap that polysomnography addresses.

treatments:
- name: Multidisciplinary Developmental and Supportive Care
  description: >-
    There is no disease-modifying or PHIP-targeted therapy. Management is
    symptomatic, developmental, and anticipatory: early-intervention services,
    individualized educational support, therapy for hypotonia and motor delay,
    feeding and gastrointestinal support, ophthalmological assessment, and
    coordinated behavioral-health care. The distinctive planning message from the
    natural-history data is that the burden shifts with age - weight and mood
    problems become more prominent after childhood - so care should be structured for
    the life course rather than front-loaded into the preschool years.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: supportive care
    term:
      id: NCIT:C15747
      label: Supportive Care
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Our findings provide additional natural history data for Chung-Jansen syndrome
      and provide opportunities for early intervention of healthy eating habits and
      awareness of developing mood and behavioral challenges over the life course.
    explanation: >-
      The cohort's own framing of management as early intervention plus life-course
      awareness.
  target_phenotypes:
  - preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay

- name: Speech and Language Therapy
  description: >-
    Speech and language therapy addresses the delayed speech milestones that are a
    common early feature and a frequent reason for referral.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: speech therapy
    term:
      id: NCIT:C159273
      label: Speech Language Therapy
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:41383545
    reference_title: "Comorbidity of Attention Deficit Hyperactivity Disorder (ADHD) and Chung-Jansen Syndrome: Case Report and Review of Literature."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Although clinical presentations vary, behavioral problems and delayed motor and
      speech milestones are common.
    explanation: >-
      Establishes the speech-delay indication; PARTIAL because no CHUJANS-specific
      speech-therapy outcome study exists.
  target_phenotypes:
  - preferred_term: Delayed speech and language development
    term:
      id: HP:0000750
      label: Delayed speech and language development

- name: Physical Therapy
  description: >-
    Physiotherapy targets the hypotonia, motor delay, and balance/coordination
    difficulty that affect the large majority of individuals. The rationale is the
    documented motor phenotype; no CHUJANS-specific rehabilitation trial exists.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: physical therapy
    term:
      id: NCIT:C15302
      label: Physical Therapy
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Other common symptoms were hypotonia (78.7%)
    explanation: >-
      Documents the indication (hypotonia in ~79%); PARTIAL because the therapy
      itself is not evaluated in the source.
  target_phenotypes:
  - preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia

- name: Occupational Therapy
  description: >-
    Occupational therapy addresses fine-motor and daily-living function. It is
    curated separately from physiotherapy because the adaptive-functioning data give
    it its own indication: daily-living-skills percentiles were low across the
    cohort, and socialisation scores were low in every individual assessed, so the
    functional deficit is not reducible to the motor phenotype physiotherapy
    addresses.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: occupational therapy
    term:
      id: NCIT:C121351
      label: Occupational Therapy
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:31167805
    reference_title: "Clinical and genetic characterization of individuals with predicted deleterious PHIP variants."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      age-adjusted percentiles varied in communication (1%-42%; average:11.8%,
      median: 8%) and daily living skills (1%-50%; average: 12.6%, median 4%)
    explanation: >-
      Quantifies the daily-living-skills deficit that occupational therapy targets;
      PARTIAL because the therapy itself is not evaluated in the source.
  target_phenotypes:
  - preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay

- name: Early Dietary and Weight-Management Intervention
  description: >-
    Because overweight and obesity emerge over time rather than being present from
    birth and become more prevalent after age 12, the natural-history data argue for
    establishing healthy eating habits early - before weight problems appear - rather
    than treating obesity reactively. This is the one management recommendation that
    follows directly from the syndrome's own mechanistic and longitudinal data
    (reduced POMC-melanocortin satiety signaling with age-dependent weight gain), and
    it is preventive in intent.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: dietary intervention
    term:
      id: NCIT:C15447
      label: Dietary Intervention
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      provide opportunities for early intervention of healthy eating habits
    explanation: >-
      The explicit dietary-intervention recommendation from the natural-history
      cohort.
  target_phenotypes:
  - preferred_term: Obesity
    term:
      id: HP:0001513
      label: Obesity
  target_mechanisms:
  - target: Obesity and Overweight
    treatment_effect: INHIBITS
    description: >-
      Behavioral energy-balance management does not correct the upstream melanocortin
      deficit; it opposes the downstream weight outcome by constraining energy
      intake. The edge therefore targets the weight node rather than the
      satiety-signaling node, where an INHIBITS edge would read backwards.

- name: Continuous Positive Airway Pressure for Obstructive Sleep Apnea
  description: >-
    In the one CHUJANS patient with polysomnographically confirmed severe
    REM-predominant obstructive sleep apnea, CPAP improved respiratory and sleep
    quality indices and was well tolerated - which matters because tolerance of
    positive-airway-pressure therapy cannot be assumed in a population with
    intellectual disability. Evidence is a single case.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: continuous positive airway pressure
    term:
      id: NCIT:C124040
      label: Continuous Positive Airway Pressure
  therapeutic_modality: DEVICE
  evidence:
  - reference: PMID:41751879
    reference_title: "Sleep-Disordered Breathing in Chung-Jansen Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Treatment with continuous positive airway pressure improved respiratory and
      sleep quality indices and was well tolerated.
    explanation: >-
      Direct outcome evidence for CPAP in a molecularly confirmed CHUJANS patient.
  target_phenotypes:
  - preferred_term: Obstructive sleep apnea
    term:
      id: HP:0002870
      label: Obstructive sleep apnea

- name: Longitudinal Behavioral-Health, Weight, and Urorenal Surveillance
  description: >-
    Three surveillance streams are specifically indicated by the CHUJANS literature
    rather than by generic syndromic practice: mood and behavior into adolescence and
    adulthood, because depression is significantly more frequent after age 12; BMI
    over time, because obesity emerges and increases with age; and urorenogenital
    evaluation, because CAKUT is a variably expressive part of the spectrum that was
    missed in the original delineation. Endocrine assessment (thyroid function,
    glucose tolerance, reproductive endocrine status) has also been proposed on the
    basis of a detailed adult workup. Recorded with the generic NCIT disease-screening
    action because NCIT has no clinical-intervention term for longitudinal
    surveillance.
  action_category: SCREENING
  treatment_term:
    preferred_term: complication surveillance
    term:
      id: NCIT:C15419
      label: Disease Screening
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:37961033
    reference_title: "Clinical phenotypes of individuals with Chung-Jansen syndrome across age groups."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      awareness of developing mood and behavioral challenges over the life course
    explanation: >-
      Supports the behavioral-health surveillance stream.
  - reference: PMID:39156152
    reference_title: "Pathogenic PHIP Variants are Variably Associated With CAKUT."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Conversely, patients with CHUJANS should be clinically evaluated for
      urorenogenital manifestations.
    explanation: >-
      Supports the urorenal surveillance stream.
  - reference: PMID:42355777
    reference_title: "Chung-Jansen Syndrome in a Young Woman with a PHIP Variant: Severe Obesity, Intellectual Disability, and Endocrine Abnormalities."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This case suggests the inclusion of comprehensive endocrine evaluations in
      future studies on patients with Chung-Jansen syndrome, in order to support
      endocrine work-up and facilitate early identification and appropriate
      management of potentially treatable alterations.
    explanation: >-
      Proposes endocrine surveillance; PARTIAL because it is a single-case
      recommendation framed as a suggestion for future study.

- name: Genetic Counseling and Parental Testing
  description: >-
    Counseling must cover the 50% transmission risk for an affected heterozygote and,
    more subtly, the fact that a clinically unremarkable parent may nonetheless carry
    the variant - inherited alleles from mildly affected parents are well documented,
    and severity cannot be predicted from genotype. Parental testing is therefore not
    optional bookkeeping but the step that determines recurrence risk and identifies
    previously undiagnosed relatives.
  action_category: COUNSELING_INFORMATIONAL
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      outlines the importance of a thorough clinical evaluation combined with genetic
      analyses for accurate diagnosis and counselling
    explanation: >-
      The cohort's explicit counseling recommendation, grounded in the observed
      inherited cases.
  - reference: PMID:39437749
    reference_title: "Novel Insights: A Novel PHIP Variant in a Family with Severe Early-Onset Obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Our finding expands the spectrum of disease-causing variants in PHIP and
      demonstrates variable intrafamilial clinical expressivity and severity.
    explanation: >-
      Documents the intrafamilial variability that counseling must convey.

clinical_trials:
- name: NCT01238250
  description: >-
    Simons Searchlight, an international online observational registry that collects
    medical, behavioral, learning, and developmental data plus biospecimens from
    families with rare genetic variants causing neurodevelopmental disorders. It is
    the main real-world data-collection route available to CHUJANS families and the
    most concrete existing mechanism for overcoming the small-cohort problem in this
    disorder. It is observational and does not test any treatment.
  evidence:
  - reference: clinicaltrials:NCT01238250
    supports: PARTIAL
    evidence_source: OTHER
    snippet: >-
      Simons Searchlight is an observational, online, international research program
      for families with rare genetic variants that cause neurodevelopmental disorders
      and may be associated with autism.
    explanation: >-
      Confirms the registry's design and scope. Support is PARTIAL because the cached
      ClinicalTrials.gov record describes eligibility generically as rare genetic
      variants that cause neurodevelopmental disorders and does not itself name PHIP,
      so PHIP-specific eligibility is not verifiable from this record.

differential_diagnoses:
- name: Prader-Willi syndrome
  description: >-
    The archetypal intellectual-disability-plus-obesity syndrome and the first
    differential a clinician will reach for. Discriminators favouring Prader-Willi
    are neonatal hypotonia with failure to thrive followed by a distinct hyperphagic
    phase, hypogonadism, short stature, and the 15q11-q13 imprinting mechanism.
    Objective facial phenotyping separates the two: PHIP patients differ
    significantly from the average Prader-Willi face.
  disease_term:
    preferred_term: Prader-Willi syndrome
    term:
      id: MONDO:0008300
      label: Prader-Willi syndrome
  evidence:
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      show a significant difference to the average face of healthy individuals as
      well as to individuals with Prader-Willi syndrome (PWS, OMIM #176270)
    explanation: >-
      GestaltMatcher analysis explicitly separates the CHUJANS facial gestalt from
      Prader-Willi.

- name: X-linked intellectual disability, Cabezas type (CUL4B)
  description: >-
    Mechanistically the closest neighbour: CUL4B is the cullin scaffold of the very
    CRL4 ligase for which PHIP is a substrate receptor, and CUL4B deficiency causes
    intellectual disability with central obesity, muscle wasting, and dysmorphism -
    an overlap that was itself used as an argument that PHIP acts through the
    ubiquitin ligase pathway. Discriminators are the X-linked inheritance and male
    predominance of the CUL4B disorder; facial phenotyping also separates the two.
  disease_term:
    preferred_term: Cabezas syndrome
    term:
      id: MONDO:0010306
      label: X-linked intellectual disability, Cabezas type
  evidence:
  - reference: PMID:27900362
    reference_title: "De novo PHIP-predicted deleterious variants are associated with developmental delay, intellectual disability, obesity, and dysmorphic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      CUL4B deficiency has been associated with intellectual disability, central
      obesity, muscle wasting, and dysmorphic features.
    explanation: >-
      States the overlapping CUL4B phenotype that makes it a differential and a
      mechanistic neighbour.
  - reference: PMID:36726590
    reference_title: "PHIP-associated Chung-Jansen syndrome: Report of 23 new individuals."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      or with a CUL4B-alteration (Intellectual developmental disorder, X-linked,
      syndromic, Cabezas type, OMIM #300354)
    explanation: >-
      Facial phenotyping separates CHUJANS from the CUL4B disorder.

- name: Cornelia de Lange syndrome
  description: >-
    The prominent/full eyebrows with synophrys, anteverted nares, and long philtrum
    make CHUJANS a genuine phenocopy of the CdLS facial gestalt, and at least one
    family was worked up as CdLS - with an initially negative CdLS-focused exome
    reanalysis - before the PHIP variant was found. Discriminators favouring CdLS are
    upper-limb reduction defects, marked growth restriction, hirsutism, and
    cohesin-complex genes. The published recommendation is to include PHIP in
    CdLS-spectrum gene analysis.
  disease_term:
    preferred_term: Cornelia de Lange syndrome
    term:
      id: MONDO:0016033
      label: Cornelia de Lange syndrome
  evidence:
  - reference: PMID:36843271
    reference_title: "Chung-Jansen syndrome can mimic Cornelia de Lange syndrome: Another player among chromatinopathies?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      CHUJANS shows a significant overlap with the CdLS spectrum, with specific
      regard to facial gestalt.
    explanation: >-
      Establishes the facial overlap that drives the diagnostic confusion.
  - reference: PMID:36843271
    reference_title: "Chung-Jansen syndrome can mimic Cornelia de Lange syndrome: Another player among chromatinopathies?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we suggest to include PHIP among genes routinely analyzed in patients belonging
      to the CdLS spectrum
    explanation: >-
      The practical testing recommendation that follows from the overlap.

- name: Borjeson-Forssman-Lehmann syndrome (PHF6)
  description: >-
    An X-linked intellectual disability syndrome with obesity that is both a clinical
    and a molecular neighbour: its DNA methylation episignature partially overlaps
    that of CHUJANS, and a combined episignature covering both disorders (plus
    White-Kernohan syndrome) has been developed. This overlap is not coincidence -
    PHF6, like PHIP, is a chromatin-associated protein - which is precisely why an
    episignature result should be interpreted as evidence about this functional group
    rather than as a single-gene readout.
  disease_term:
    preferred_term: Borjeson-Forssman-Lehmann syndrome
    term:
      id: MONDO:0010537
      label: Borjeson-Forssman-Lehmann syndrome
  evidence:
  - reference: PMID:38787418
    reference_title: "The detection of a strong episignature for Chung-Jansen syndrome, partially overlapping with Borjeson-Forssman-Lehmann and White-Kernohan syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Börjeson-Forssman-Lehmann syndrome (caused by variants in PHF6 gene)
    explanation: >-
      Named as one of the two functionally related, clinically partially overlapping
      disorders sharing methylation-profile similarity with CHUJANS.

- name: White-Kernohan syndrome (DDB1)
  description: >-
    Caused by variants in DDB1, the CRL4 adaptor that PHIP itself docks onto as a
    substrate receptor - so this is the most direct pathway-level differential in the
    set. It shares a partially overlapping methylation episignature with CHUJANS, and
    the two are handled together in the combined episignature classifier.
  disease_term:
    preferred_term: White-Kernohan syndrome
    term:
      id: MONDO:0859169
      label: White-Kernohan syndrome
  evidence:
  - reference: PMID:38787418
    reference_title: "The detection of a strong episignature for Chung-Jansen syndrome, partially overlapping with Borjeson-Forssman-Lehmann and White-Kernohan syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      White-Kernohan syndrome (caused by variants in DDB1 gene)
    explanation: >-
      Named as the other functionally related disorder sharing an overlapping
      episignature; DDB1 is the CRL4 adaptor PHIP works through.

- name: Pitt-Hopkins syndrome (TCF4)
  description: >-
    Not a classical CHUJANS differential, but added because a child whose
    craniofacial phenotype and Face2Gene analysis both suggested a
    Pitt-Hopkins-like condition was found instead to carry a novel PHIP variant,
    expanding the recognized phenotypic spectrum. The lesson is that facial-analysis
    software pointing away from CHUJANS does not exclude it.
  disease_term:
    preferred_term: Pitt-Hopkins syndrome
    term:
      id: MONDO:0012589
      label: Pitt-Hopkins syndrome
  evidence:
  - reference: PMID:39594970
    reference_title: "Broadening the PHIP-Associated Neurodevelopmental Phenotype."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The unusual clinical presentation of this novel patient resembles a PTHS-like
      condition. However, a novel variant in PHIP has been unexpectedly detected,
      expanding the phenotypic spectrum of CHUJANS.
    explanation: >-
      Documents the PTHS-like presentation resolved as CHUJANS.

discussions:
- discussion_id: chujans_pomc_mechanism_cell_context
  prompt: >-
    Does the demonstration that nuclear PHIP enhances POMC transcription, and that
    disease variants repress it, hold in human hypothalamic POMC neurons - the cells
    where the mechanism must operate for it to explain the obesity phenotype?
  kind: HUMAN_MODEL_MISMATCH
  status: OPEN
  attaches_to:
  - pathophysiology#Repressed POMC Transcription
  - pathophysiology#Impaired Central Melanocortin Satiety Signaling
  rationale: >-
    The POMC branch is the best-developed mechanistic account of any CHUJANS feature,
    but it rests on cell-based reporter and localization experiments rather than on
    human hypothalamic neurons, and the clinical phenotype it purports to explain is
    not fully penetrant - roughly 44% of individuals in the largest cohort are
    neither obese nor overweight. Two failure modes are therefore live: the effect
    could be real but quantitatively insufficient on its own, requiring modifiers to
    produce obesity; or it could be a property of the assay context. Either way the
    inference from a transfected-cell reporter to arcuate POMC neuron biology is
    currently unbridged, and the entry's mechanism_confidence values for this arm
    (PROVISIONAL, not ESTABLISHED) reflect that.
  proposed_experiments:
  - experiment_id: exp_chujans_ipsc_hypothalamic_pomc
    name: PHIP allelic series in human iPSC-derived hypothalamic POMC neurons
    description: >-
      In an isogenic human iPSC background, build a PHIP allelic series (heterozygous
      null, plus heterozygous patient truncating and missense alleles) and
      differentiate to arcuate-like hypothalamic
      cultures containing POMC neurons. Read out POMC transcript and peptide levels,
      leptin responsiveness, PHIP occupancy at the POMC locus, and the local
      chromatin marks PHIP reads (H3K4me3, H3K14ac, H4K12ac). This tests, at
      human-matched zygosity and in the correct cell type, whether the reporter
      finding reproduces and whether it is chromatin-reading-dependent.
    experiment_type:
      preferred_term: isogenic allelic-series loss-of-function experiment

- discussion_id: chujans_chromatin_reader_to_neurodevelopment_gap
  prompt: >-
    Which genes and regulatory elements lose PHIP-dependent chromatin reading and
    CRL4 recruitment in the developing human brain, and how does that produce the
    specific CHUJANS neurodevelopmental and behavioral phenotype?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Failure of CRL4 Substrate-Receptor Recruitment to Chromatin
  - pathophysiology#Disrupted Neurodevelopmental Gene Expression Program
  rationale: >-
    The molecular top of the pathograph is unusually well resolved for a
    chromatinopathy - the reader domains, their histone marks, the CRL4 recruitment
    step, and a patient-level methylation episignature are all established - and the
    clinical bottom is well characterized across three cohorts. The middle is empty.
    No CHUJANS-specific patient neuron, brain organoid, or brain transcriptomic
    dataset exists, so no mis-regulated target gene has been identified, and the
    episignature's differentially methylated loci have not been connected to
    neurodevelopmental effector genes. This is why the neurodevelopmental node in
    this entry is tagged HYPOTHETICAL despite the phenotype itself being certain: the
    uncertainty is about the route, not the destination.
  proposed_experiments:
  - experiment_id: exp_chujans_chip_and_transcriptome_neurons
    name: PHIP and CRL4 chromatin occupancy plus transcriptome in PHIP-haploinsufficient human neurons
    description: >-
      Map PHIP and CUL4/DDB1 occupancy genome-wide (CUT&RUN or ChIP-seq) in wild-type
      versus PHIP-haploinsufficient human iPSC-derived cortical neurons and
      progenitors, alongside RNA-seq, ATAC-seq, and profiling of H3K4me3, H3K14ac,
      and H4K12ac. Intersect sites of lost PHIP/CRL4 occupancy with differentially
      expressed genes and with the differentially methylated loci that define the
      blood episignature, to identify candidate effector genes bridging the reader
      defect and the neurodevelopmental phenotype.
    experiment_type:
      preferred_term: chromatin occupancy and transcriptome profiling

- discussion_id: chujans_replication_instability_clinical_consequence
  prompt: >-
    Does the replication-fork protection defect caused by CHUJANS PHIP/DCAF14
    variants produce any measurable clinical consequence - genome instability, cancer
    predisposition, or a contribution to the neurodevelopmental phenotype - in
    affected individuals?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Replication Fork Destabilization Under Replication Stress
  rationale: >-
    Two patient missense alleles demonstrably impair replication fork progression and
    stalled-fork protection, and the authors explicitly predict
    replication-associated genome instability in the syndrome. But that prediction
    has never been tested in patients: no CHUJANS cohort has been screened for
    chromosomal instability, no cancer incidence data exist, and the tested alleles
    are two missense variants rather than the truncating alleles that dominate the
    reported spectrum. PHIP expression alterations are separately linked to cancer,
    which makes the question non-trivial rather than academic. Until it is answered,
    this arm cannot be given a clinical downstream and no surveillance recommendation
    can be justified from it.
  proposed_experiments:
  - experiment_id: exp_chujans_patient_genome_instability
    name: Genome-instability and neoplasia assessment in a CHUJANS cohort
    description: >-
      In patient-derived lymphoblastoid or fibroblast lines spanning truncating,
      deletion, and missense PHIP alleles, measure baseline and induced chromosomal
      instability (micronucleus formation, chromosome aberrations, replication-stress
      markers, DNA fiber fork progression) against controls. In parallel, assemble
      cancer and neoplasia incidence from an international CHUJANS registry cohort
      (for example via Simons Searchlight) to determine whether the in vitro defect
      has any epidemiological correlate.
    experiment_type:
      preferred_term: patient-derived cell genome instability assay

- discussion_id: chujans_population_prevalence_unknown
  prompt: >-
    What is the true population prevalence of Chung-Jansen syndrome, and how much of
    the apparent rarity is underdiagnosis of mildly affected individuals?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#PHIP Haploinsufficiency
  rationale: >-
    No validated prevalence or incidence estimate exists; only cumulative published
    case counts on the order of one hundred individuals. Two features make the
    published count a likely underestimate rather than a reasonable proxy: alleles
    are repeatedly inherited from parents whose learning, behavioral, or weight
    phenotype was recognized only after their child was diagnosed, and the cardinal
    features (mild learning difficulty, ADHD, anxiety, overweight) are individually
    common and unlikely to trigger genetic testing in isolation. Reliable
    denominators would come from unbiased population-scale sequencing rather than
    from further clinically ascertained cohorts.
  proposed_experiments:
  - experiment_id: exp_chujans_biobank_prevalence
    name: Population-scale PHIP loss-of-function ascertainment with reverse phenotyping
    description: >-
      Query large unselected biobank and population sequencing resources for
      high-confidence PHIP loss-of-function alleles, then reverse-phenotype carriers
      for cognitive, behavioral, anthropometric, and urorenal traits. This yields both
      a genotype-first prevalence estimate and a penetrance estimate for each cardinal
      feature that is not distorted by clinical ascertainment.
    experiment_type:
      preferred_term: genotype-first population cohort study

📚

References & Deep Research

Deep Research

1

Falcon ▸

Disease Characteristics Research Template

Edison Scientific Literature 23 citations 2026-08-01T18:58:43.805131

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

Disease Name: Chung-Jansen Syndrome
MONDO ID: (if available)
Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Chung-Jansen Syndrome covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

What is the disease? Provide a concise overview.
What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
What are the common synonyms and alternative names?
Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
Risk Factors:

Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
Genetic risk factors (causal variants, susceptibility loci, modifier genes)
Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
Protective Factors:

Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
Genetic protective factors (protective variants, modifier alleles)
Environmental protective factors (diet, lifestyle, exposures that reduce risk)
Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
Pathogenic Variants:
Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
Variant type/class (missense, frameshift, nonsense, splice-site, structural)
Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
Functional consequences (loss of function, gain of function, dominant negative)
Modifier Genes: Genes that modify disease severity or expression
Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

Search first: CDC databases, WHO, PubMed, NHANES
Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

Search first: PubMed, Gene Ontology, Reactome
Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Molecular Profiling (if available):
Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
Advanced Technologies (if applicable):
Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

Organ Level:
Primary organs directly affected
Secondary organ involvement (complications, secondary effects)
Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
Tissue and Cell Level:
Specific tissue types affected (epithelial, connective, muscle, nervous)
Specific cell populations targeted (with Cell Ontology terms)

Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
Subcellular Level:
Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
Localization:
Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

Onset:
Typical age of onset (congenital, pediatric, adult, geriatric)
Onset pattern (acute, subacute, chronic, insidious)

Search first: OMIM, Orphanet, HPO, PubMed
Progression:
Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
Progression rate (rapid, slow, variable)
Disease course pattern (episodic, relapsing-remitting, progressive, stable)
Disease duration (self-limited, chronic lifelong)

Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
Patterns:
Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

Epidemiology:
Prevalence (cases per 100,000 at given time)
Incidence (new cases per 100,000 per year)

Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
For Genetic Etiology:
Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
Population Demographics:
Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
Geographic distribution of specific variants
Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

Clinical Tests:
Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
Genetic Testing:

Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
Overview of recommended genetic testing approach
Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
FISH > Search first: ClinVar, cytogenetics databases, PubMed
Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
Omics-Based Diagnostics (if applicable):
RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
Clinical Criteria:
Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
Screening:
Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

Survival and Mortality:
Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
Morbidity and Function:
Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
Disease Course:
Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
Prediction:
Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

Pharmacotherapy:
Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
Advanced Therapeutics:
Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
Surgical and Interventional:
Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
Supportive and Rehabilitative:
Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
Experimental:
Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
Treatment Outcomes:
Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
Treatment Strategy:
Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest NCIT (NCI Thesaurus) clinical-intervention terms where applicable.

13. Prevention

Prevention Levels:
Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
Immunization: Vaccine strategies (if applicable)

Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
Screening and Early Detection:
Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
Behavioral Interventions: Lifestyle modifications to reduce risk

Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
Counseling: Genetic counseling (risk assessment, family planning guidance)

Search first: NSGC resources, ACMG guidelines, GeneReviews
Public Health:
Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
Prophylaxis: Preventive medications or procedures

Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

Taxonomy: Species affected (with NCBI Taxon identifiers)

Search first: NCBI Taxonomy
Breed: Specific breeds affected (with VBO identifiers if applicable)

Search first: VBO (Vertebrate Breed Ontology)
Gene: Orthologous genes in other species (with NCBI Gene IDs)

Search first: NCBI Gene
Natural Disease:
Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
Comparative Biology:
Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
Transmission (if applicable):
Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

Model Types:
Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
Genetic Models:
Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
Model Characteristics:
Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
Applications:
Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
Resources:
Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

Cite primary literature (PMID preferred) for all mechanistic and clinical claims
Prioritize recent reviews and landmark papers
Include direct quotes from abstracts where possible to support key statements
Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, NCIT, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (NCIT terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Chung–Jansen syndrome: disease-characteristics research report

Executive summary

Chung–Jansen syndrome (CHUJANS) is a rare, autosomal-dominant Mendelian neurodevelopmental disorder caused principally by heterozygous loss of function of PHIP. Its core phenotype comprises developmental delay or intellectual/learning disability, behavioral or psychiatric abnormalities, a recognizable facial gestalt, and variably penetrant overweight or obesity. In the largest recent primary cohort available here—23 newly described individuals—developmental delay occurred in 22/23, learning disability/intellectual disability in 22/23, behavioral abnormalities in 20/23, weight problems in 13/23, and characteristic craniofacial findings in 23/23. Both de novo variants and transmission from mildly affected parents occur, demonstrating marked variable expressivity. (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)

The most developed mechanistic model links deficient nuclear PHIP activity to reduced POMC transcription and impaired anorexigenic leptin–melanocortin signaling. Cellular experiments found that all tested disease/obesity-associated PHIP mutants reduced POMC-reporter activity; four variants showed dose-dependent dominant-negative effects, and case variants significantly reduced the nuclear-to-cytoplasmic PHIP ratio. This mechanism plausibly explains obesity but does not yet fully explain the neurodevelopmental phenotype. (marenne2020exomesequencingidentifies pages 5-6, marenne2020exomesequencingidentifies pages 10-11)

Topic	Key finding	Evidence / source
Identity / identifiers	Chung-Jansen syndrome (CHUJANS), also called DIDOD syndrome; OMIM disease identifier reported as #617991. Disease-level identifiers beyond OMIM (e.g., MONDO, HPO set) should be treated as needing database validation if not independently verified.	2023 cohort paper states CHUJANS, OMIM #617991; PHIP gene OMIM *612870 (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)
Causal gene and mechanism	Primary causal gene is PHIP (pleckstrin homology domain interacting protein). Current understanding supports PHIP haploinsufficiency as the main disease mechanism; variant classes include truncating, missense, splice, and larger deletions.	Kampmeier et al., 2023, Front Cell Dev Biol, DOI: https://doi.org/10.3389/fcell.2022.1020609 (kampmeier2023phipassociatedchungjansensyndrome pages 1-2)
Inheritance	Usually autosomal dominant with many de novo cases, but inherited cases from mildly affected parents are documented, indicating variable expressivity and likely reduced/variable penetrance in some families. In the 23-person 2023 cohort, inheritance was seen in multiple maternal or paternal transmissions.	2023 cohort summary and segregation analysis (Sanger/qPCR/FISH) (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)
Strongest 2023 phenotype frequencies	In 23 newly reported individuals: developmental delay 22/23, learning disability/intellectual disability 22/23, behavioral abnormalities 20/23, weight problems 13/23, and characteristic craniofacial features 23/23; cohort included 13 males / 10 females. Facial pattern included large ears/earlobes, prominent eyebrows, anteverted nares, and long philtrum.	Kampmeier et al., 2023, DOI: https://doi.org/10.3389/fcell.2022.1020609 (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 1-2, kampmeier2023phipassociatedchungjansensyndrome pages 3-5)
Clinical course / phenotype interpretation	Neurodevelopmental and behavioral features begin in childhood; obesity/overweight is common but variably penetrant and may emerge from childhood to puberty. Behavioral issues can include impulsivity, aggression, anxiety, hyperactivity, and autism-spectrum features; regular follow-up into adulthood was recommended.	2023 cohort interpretation (kampmeier2023phipassociatedchungjansensyndrome pages 10-11)
Molecular evidence	PHIP has both cytoplasmic and nuclear functions. Functional data support obesity pathogenesis through impaired POMC transcription in the leptin-melanocortin pathway. Wild-type PHIP enhanced POMC transcription, whereas all tested PHIP mutants reduced it; some variants showed dominant-negative effects. Case variants also decreased the nuclear:cytoplasmic PHIP ratio (p=0.004).	Marenne et al., 2020, Cell Metab, DOI: https://doi.org/10.1016/j.cmet.2020.05.007 (marenne2020exomesequencingidentifies pages 5-6, marenne2020exomesequencingidentifies pages 10-11, marenne2020exomesequencingidentifies pages 1-3)
Obesity genetics signal	In severe childhood obesity sequencing analyses, PHIP showed an excess burden of very rare predicted deleterious variants; reported enrichment for obese cases had p=4.58×10^-4 and OR=2.4 [1.5–3.84].	Marenne et al., 2020, DOI: https://doi.org/10.1016/j.cmet.2020.05.007 (marenne2020exomesequencingidentifies pages 5-6)
Additional mechanistic biology	Published disease discussions also connect PHIP disruption with replication fork stability / genome integrity defects, although disease-specific pathway resolution remains incomplete.	2023 disease cohort discussion (kampmeier2023phipassociatedchungjansensyndrome pages 12-13)
Diagnostics	Diagnosis is currently based on genetic testing plus clinical evaluation. Methods reported include microarray, gene panels, exome sequencing, followed by Sanger sequencing, qPCR, and FISH for confirmation/segregation. PHIP should be considered on DD/ID/behavioral abnormality/obesity panels. Facial phenotyping tools such as GestaltMatcher may support recognition but are not standalone diagnostics.	Kampmeier et al., 2023, DOI: https://doi.org/10.3389/fcell.2022.1020609 (kampmeier2023phipassociatedchungjansensyndrome pages 1-2, kampmeier2023phipassociatedchungjansensyndrome pages 3-5, kampmeier2023phipassociatedchungjansensyndrome pages 11-12)
Real-world implementation / registries	The main identified implementation resource is Simons Searchlight (NCT01238250), a recruiting, international, longitudinal observational registry collecting medical, behavioral, developmental, and genetic data from individuals with eligible neurodevelopmental genetic conditions, including PHIP-related disorders. It does not test treatments.	ClinicalTrials.gov NCT01238250 / Simons Searchlight (NCT01238250 chunk 1, NCT01238250 chunk 2)
Management / treatment	No disease-specific, evidence-based disease-modifying therapy or interventional trial was identified in the retrieved evidence. Current care is multidisciplinary and phenotype-directed: developmental/behavioral assessment, educational supports, obesity surveillance and management, and genetic counseling for families.	Derived from absence of interventional trial evidence plus cohort recommendations for follow-up (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, NCT01238250 chunk 1, NCT01238250 chunk 2)
Major evidence gaps	Population prevalence/incidence, validated survival data, disease-specific quality-of-life measures, penetrance estimates, genotype-phenotype correlations, standardized treatment algorithms, and validated MONDO/HPO identifier set remain insufficiently defined in the retrieved evidence. Disease-specific single-cell, spatial transcriptomic, proteomic, and metabolomic studies were not identified here.	Evidence gap synthesis from available cohort/mechanistic/registry sources (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, marenne2020exomesequencingidentifies pages 5-6, NCT01238250 chunk 1)

Table: This table condenses the highest-yield disease knowledge-base facts for Chung-Jansen syndrome, including identifiers, genetics, phenotype frequencies, mechanism, diagnostics, management, and evidence gaps. It is designed as a compact reference for curation and downstream database entry.

Evidence scope and limitations

The strongest disease-specific sources retrieved were Kampmeier et al., published 16 January 2023, reporting 23 individuals (DOI), and Marenne et al., published June 2020, providing human genetic and functional evidence for PHIP in severe childhood obesity (DOI). PMID values were not exposed in the retrieved records and therefore are not supplied rather than guessed. The literature remains dominated by small, clinically ascertained cohorts and case reports; frequency estimates should not be interpreted as population prevalence. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, marenne2020exomesequencingidentifies pages 5-6)

1. Disease information

Definition. CHUJANS is a congenital/early-childhood neurodevelopmental syndrome due to PHIP dosage or functional deficiency. The disorder combines cognitive-developmental impairment, behavioral abnormalities, dysmorphic facial features, and susceptibility to excessive weight gain. (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)

Identifiers and names.

OMIM: #617991.
Causal-gene OMIM: PHIP, *612870.
Common names: Chung–Jansen syndrome; PHIP-associated Chung–Jansen syndrome; PHIP-related disorder; DIDOD syndrome (“developmental delay, intellectual disability, obesity, and dysmorphism”). (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)
MONDO: a stable MONDO identifier was not verified in the retrieved evidence and should be validated directly against the current MONDO release before database ingestion.
Orphanet, MeSH, ICD-10/ICD-11: no disease-specific identifiers were established by the retrieved primary literature. In practice, manifestations are coded separately—for example intellectual disability, developmental disorder, behavioral disorder, or obesity—rather than through a uniquely validated CHUJANS ICD code.

The evidence summarized here is aggregated disease-level evidence from research cohorts and registries, not individual EHR-derived information. The 2023 cohort collected standardized clinical and genetic information from referring geneticists in six European countries; it included 13 males and 10 females. (kampmeier2023phipassociatedchungjansensyndrome pages 3-5)

Representative exact abstract statement: “almost all individuals reported here show developmental delay (22/23), learning disability or ID (22/23), behavioral abnormalities (20/23), weight problems (13/23) and characteristic craniofacial features … (23/23).” (kampmeier2023phipassociatedchungjansensyndrome pages 1-2)

2. Etiology, risk, and protective factors

Causal factors

The primary cause is a heterozygous germline pathogenic PHIP alteration, most commonly producing haploinsufficiency. Reported classes include nonsense and frameshift variants, splice variants, missense substitutions, intragenic/whole-gene deletions, and larger deletions involving PHIP plus neighboring genes. Larger deletions may produce blended or more complex phenotypes because additional genes are affected. (kampmeier2023phipassociatedchungjansensyndrome pages 1-2, kampmeier2023phipassociatedchungjansensyndrome pages 3-5)

Genetic risk

A pathogenic PHIP allele is the principal risk factor. Variants may arise de novo or be inherited from a mildly affected parent. Five inherited cases were documented in the 23-person cohort, supporting vertical transmission and substantial intrafamilial variability. Loss-of-function variants may be more strongly associated with obesity than missense variants, although present sample sizes are insufficient for a definitive variant-class prognosis. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, kampmeier2023phipassociatedchungjansensyndrome pages 2-3)

In severe-obesity sequencing, very rare predicted-deleterious PHIP variants were enriched in 2,737 cases versus 6,704 controls; the combined analysis reported OR 2.4, 95% CI 1.5–3.84; p=4.58×10⁻⁴. This supports PHIP as an obesity gene but did not reach a conventional exome-wide Bonferroni threshold, and obesity is not completely penetrant among CHUJANS patients. (marenne2020exomesequencingidentifies pages 5-6, marenne2020exomesequencingidentifies pages 10-11, marenne2020exomesequencingidentifies pages 1-3)

Environmental, infectious, and lifestyle factors

No toxin, infection, radiation exposure, occupation, diet, or lifestyle factor is known to cause CHUJANS. Diet, physical activity, medications, sleep, and the family environment may modify weight or behavior after onset, but disease-specific gene–environment interaction studies were not found. There is no infectious agent and no zoonotic transmission.

Protective factors

No validated protective PHIP allele, modifier gene, dietary exposure, medication, or lifestyle intervention has been shown to prevent the syndrome. Healthy nutrition and activity may mitigate secondary obesity but do not prevent the underlying neurodevelopmental disorder. Claims of molecular protection would presently be speculative.

3. Phenotypes

The following ontology terms are suggested for curation; exact HPO releases should be checked before production use.

Phenotype	Frequency/course	Suggested HPO term
Developmental delay	22/23 in the 2023 cohort; begins in infancy/childhood; chronic	Global developmental delay, HP:0001263
Learning disability/intellectual disability	22/23; usually mild-to-moderate and variable; verbal ability may exceed performance ability	Intellectual disability, HP:0001249; learning disability, HP:0001328
Speech/language delay	Common but not universal; early childhood	Delayed speech and language development, HP:0000750
Behavioral abnormalities	20/23 (87%); impulsivity, aggression, anxiety, hyperactivity, and autistic features reported	Behavioral abnormality, HP:0000708; hyperactivity, HP:0000752; anxiety, HP:0000739; autistic behavior, HP:0000729
Overweight/obesity	13/23 had weight problems; combined reports suggest approximately 56–70%; onset ranges from childhood to puberty	Obesity, HP:0001513; childhood-onset obesity, HP:0012743
Hypotonia	Common; a combined 47-person summary reported 78%	Muscular hypotonia, HP:0001252
Feeding difficulty	Frequently reported in childhood; historical cohorts reported approximately 77–100%, but definitions varied	Feeding difficulties, HP:0011968
Facial gestalt	23/23 in the 2023 cohort: large ears/earlobes, prominent eyebrows, anteverted nares, long philtrum	Large ears, HP:0000400; thick/prominent eyebrows, HP:0000574; anteverted nares, HP:0000463; long philtrum, HP:0000343
Constipation	Reported across cohorts, approximately 30–76%, depending on ascertainment	Constipation, HP:0002019
Balance/gait problems	Recurrent but incompletely quantified	Abnormality of coordination, HP:0011443 or gait abnormality, HP:0001288
Seizures	Reported minority feature; not a defining universal manifestation	Seizure, HP:0001250
Orthopedic findings	Hip dysplasia and clubfoot reported in subsets	Developmental dysplasia of the hip, HP:0001385; talipes equinovarus, HP:0001762

The cohort-level frequencies above are supported by direct denominators, whereas feeding, constipation, hypotonia, and seizure estimates vary among cohorts and ascertainment instruments. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 5-5, loid2026anovelphip pages 5-6)

Quality of life. No CHUJANS-specific EQ-5D, SF-36, PROMIS, or validated caregiver-burden study was identified. Nevertheless, cognitive limitations affect education and independent functioning; communication deficits, ADHD/autistic or aggressive behaviors affect family and social participation; hypotonia and coordination problems affect mobility; and obesity raises long-term metabolic and psychosocial burden. These are clinically plausible impacts, but quantitative CHUJANS-specific utility values are unavailable.

4. Genetic and molecular information

Gene and variant interpretation

Gene: PHIP, pleckstrin homology domain interacting protein.
Reference transcript used in the 2023 cohort: NM_017934.7. (kampmeier2023phipassociatedchungjansensyndrome pages 3-5)
Origin: constitutional/germline, not a somatic cancer disorder.
Inheritance: autosomal dominant.
Primary mechanism: haploinsufficiency; selected missense/truncating variants may also exert dominant-negative effects in reporter assays. (kampmeier2023phipassociatedchungjansensyndrome pages 1-2, marenne2020exomesequencingidentifies pages 5-6)
Population frequency expectation: truly pathogenic alleles should be absent or extremely rare in gnomAD/other reference populations. Variant-specific frequencies must be queried directly because no universal value applies.
Classification: truncating/deletion alleles affecting a loss-of-function-sensitive gene may satisfy ACMG/AMP pathogenic/likely-pathogenic evidence; missense variants require segregation, population, computational, domain, and preferably functional evidence. A VUS should not establish the diagnosis by itself.

No recurrent founder allele, anticipation, carrier frequency, or validated modifier gene has been established. Large deletions require attention to neighboring genes, while mildly affected transmitting parents demonstrate that phenotype prediction from genotype alone is unreliable. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)

Epigenetics and structural variation

A PHIP-associated DNA-methylation episignature has been reported secondarily and may overlap partially with signatures of other neurodevelopmental syndromes, suggesting possible future utility for resolving VUSs. However, the retrieved evidence did not provide sufficient primary validation metrics for routine diagnostic endorsement. (loid2026anovelphip pages 7-8, loid2026anovelphip pages 5-6)

Chromosomal microdeletions involving part or all of PHIP are established molecular causes. CMA detects copy-number loss; qPCR or FISH can confirm the deletion and parental segregation. Karyotyping is generally too low-resolution for small PHIP deletions. (kampmeier2023phipassociatedchungjansensyndrome pages 1-2)

5. Environmental information

CHUJANS is not an environmentally acquired, infectious, toxicologic, occupational, or lifestyle disease. Environmental exposures can influence downstream obesity, development, education, and behavior, as in the general population, but no CHUJANS-specific CTD-style exposure association or formal gene–environment study was identified. Smoking, alcohol, pollution, radiation, and pathogens have no established etiologic role.

6. Mechanism and pathophysiology

Upstream causal chain

Pathogenic PHIP allele → reduced or dysfunctional PHIP protein → impaired nuclear transcription/chromatin-replication functions and, for some alleles, altered intracellular localization → dysregulated developmental gene expression and POMC signaling → neurodevelopmental impairment plus reduced satiety/energy-homeostasis signaling → learning/behavioral abnormalities and obesity susceptibility.

PHIP has at least two functionally relevant contexts. A cytoplasmic approximately 104-kDa isoform interacts with IRS-1/IRS-2 and participates in insulin/IGF-1 signaling. A larger approximately 230-kDa nuclear isoform, also described as DCAF14/REPID, binds chromatin and participates in DNA replication and transcription. Disease discussions additionally implicate replication-fork stability and genome integrity. (kampmeier2023phipassociatedchungjansensyndrome pages 12-13, marenne2020exomesequencingidentifies pages 5-6)

POMC/leptin–melanocortin mechanism

Wild-type PHIP enhanced POMC transcription under basal and leptin-stimulated conditions. All tested mutant constructs reduced POMC-reporter activity, and four—T289P, D594E, Q1343X, and R1505Q—showed dose-dependent dominant-negative effects against wild-type PHIP. Case-associated variants also produced a significantly lower nuclear:cytoplasmic PHIP ratio than control variants (p=0.004). The proposed downstream consequence is diminished hypothalamic POMC-derived melanocortin signaling and impaired appetite suppression. (marenne2020exomesequencingidentifies pages 5-6, marenne2020exomesequencingidentifies pages 10-11, marenne2020exomesequencingidentifies pages 20-21)

This evidence is in vitro—HEK293/COS-7 transfection, luciferase reporters, leptin stimulation, and microscopy—not direct demonstration in patient hypothalamic neurons. It is therefore a strong mechanistic hypothesis for obesity, not yet a complete tissue-level causal proof. (marenne2020exomesequencingidentifies pages 10-11, marenne2020exomesequencingidentifies pages 20-21)

Suggested ontology annotations

GO biological processes: regulation of transcription by RNA polymerase II; DNA replication; replication-fork protection; maintenance of genome integrity; insulin receptor signaling; cellular response to leptin; regulation of feeding behavior; nervous-system development.
GO cellular components: nucleus; chromatin; cytoplasm; replication fork.
Cell Ontology candidates: neuron (CL:0000540), hypothalamic neuron, POMC-expressing neuron, neural progenitor cell, and adipocyte (CL:0000136). Only neuron-level and cell-line functional evidence is presently strong; disease-specific single-cell localization is not established.
Chemical ontology candidates: leptin, insulin, glucose, and proopiomelanocortin-derived peptides; CHEBI identifiers should be verified against the current release.

No CHUJANS-specific patient transcriptome, proteome, metabolome, lipidome, spatial transcriptome, single-cell atlas, iPSC-neuron dataset, or CRISPR screen was identified. Consequently, claims about affected neuronal subclasses, metabolic signatures, immune activation, oxidative injury, fibrosis, or organ-specific cell death would be unsupported.

7. Anatomical structures affected

The central nervous system is the principal functional system affected, manifesting through cognition, language, motor coordination, tone, and behavior. The hypothalamic appetite-control network is mechanistically implicated by POMC findings, although direct patient-tissue confirmation is lacking. Suggested anatomy terms include brain (UBERON:0000955), central nervous system (UBERON:0001017), hypothalamus (UBERON:0001898), and cerebral cortex (UBERON:0000956). (marenne2020exomesequencingidentifies pages 5-6, marenne2020exomesequencingidentifies pages 1-3)

Secondary systems include adipose/metabolic tissues through obesity; craniofacial structures through dysmorphism; gastrointestinal tract through feeding difficulty and constipation; skeletal/musculoskeletal structures through hypotonia, balance problems, hip dysplasia, or clubfoot; and, in a minority, the nervous system through seizures. No consistent lateralization has been reported. (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 5-5)

At the subcellular level, the nucleus, chromatin/replication machinery, cytoplasm, and nuclear–cytoplasmic trafficking/localization are relevant. (kampmeier2023phipassociatedchungjansensyndrome pages 12-13, marenne2020exomesequencingidentifies pages 5-6)

8. Temporal development

CHUJANS is genetically present from conception and usually becomes clinically evident in infancy or early childhood through hypotonia, feeding problems, delayed milestones, or speech/learning difficulty. Facial characteristics may become more recognizable with age. Weight gain is variable and may begin in childhood or around puberty; therefore, normal early weight does not exclude later obesity. Behavioral and psychiatric manifestations may evolve with developmental demands and warrant continued surveillance into adulthood. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, kampmeier2023phipassociatedchungjansensyndrome pages 3-5)

The course is chronic and lifelong, not relapsing-remitting. There are no validated disease stages, remission pattern, or predictable progression rate. Developmental skills may improve with therapy and education, but the genetic condition does not resolve. Early childhood is the main intervention window for speech, motor, educational, and behavioral support; longitudinal adult natural-history data remain sparse.

9. Inheritance and population

CHUJANS follows an autosomal-dominant pattern. Many affected individuals have de novo variants, but inherited disease from mildly affected mothers or fathers is established. For an affected heterozygous individual, the theoretical transmission probability is 50% per pregnancy, although clinical severity cannot be predicted reliably. Parental testing is essential because subtle learning, behavioral, or weight manifestations may only be recognized retrospectively. (kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)

Penetrance is not formally quantified and may be incomplete for individual manifestations—especially obesity—while expressivity is clearly variable. Germline mosaicism has not been quantified; after an apparently de novo result, recurrence risk is low but not zero because parental gonadal mosaicism cannot be excluded. No anticipation, founder effect, consanguinity association, ethnic enrichment, or geographic concentration has been established.

Population prevalence, incidence, carrier frequency, mortality, and age distribution are unknown. The 2023 cohort’s sex distribution—13 males and 10 females—does not support a meaningful sex bias and is consistent with autosomal inheritance. (kampmeier2023phipassociatedchungjansensyndrome pages 3-5)

10. Diagnostics

Recommended approach

Clinical suspicion: developmental/learning disability plus behavioral problems, characteristic facial features, hypotonia or coordination problems, and/or childhood-onset overweight/obesity.
First-line genomic testing: trio exome or genome sequencing, or a comprehensive neurodevelopmental/syndromic-obesity panel that includes PHIP. Exome sequencing was a major discovery route in reported patients. (kampmeier2023phipassociatedchungjansensyndrome pages 3-5)
Copy-number assessment: ensure the platform detects exon-level/whole-gene deletions; otherwise add CMA or validated deletion/duplication analysis.
Confirmation and segregation: Sanger sequencing for sequence variants; qPCR/MLPA or orthogonal CNV assay for deletions; parental testing for inheritance and counseling. FISH may be useful for sufficiently large rearrangements. (kampmeier2023phipassociatedchungjansensyndrome pages 1-2)
Variant interpretation: apply ACMG/AMP criteria, phenotype fit, de novo/segregation data, gnomAD absence, and functional evidence. Do not use facial analysis alone.

WGS may detect sequence variants, CNVs, and structural/regulatory changes missed by panel or exome testing. RNA sequencing could clarify a suspected splice variant, and methylation profiling may eventually help selected VUS cases, but neither is yet a validated routine CHUJANS biomarker in the retrieved evidence.

There is no diagnostic blood chemistry, enzyme assay, metabolite, biopsy, EEG pattern, MRI signature, or circulating biomarker. EEG is indicated for suspected seizures; MRI, endocrine/metabolic laboratory testing, orthopedic imaging, sleep evaluation, and gastrointestinal assessment should be symptom-directed.

Differential diagnosis

Important differentials include Prader–Willi syndrome, CUL4B-related Cabezas syndrome, other syndromic/monogenic obesity disorders, and neurodevelopmental syndromes with dysmorphism. GestaltMatcher analysis separated the average PHIP facial pattern from healthy controls, Prader–Willi syndrome, and CUL4B-related disorder, but could not reliably distinguish PHIP missense from loss-of-function or splice classes. Thus, facial AI is an adjunct to—not a replacement for—molecular testing. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, kampmeier2023phipassociatedchungjansensyndrome pages 2-3, kampmeier2023phipassociatedchungjansensyndrome pages 11-12)

No population newborn screen is available. Cascade testing is appropriate after a familial pathogenic variant is identified.

11. Outcome and prognosis

No 5- or 10-year survival estimates, disease-specific mortality rate, or validated life-expectancy estimate exists. The available phenotype does not indicate a uniformly lethal disorder, but adult follow-up is too limited for strong longevity conclusions. Morbidity is primarily developmental, educational, behavioral, motor, and metabolic.

Long-term complications may include reduced independence, persistent communication/learning needs, psychiatric or behavioral morbidity, and obesity-associated hypertension, dyslipidemia, insulin resistance, fatty liver disease, sleep-disordered breathing, and orthopedic burden. These metabolic complications are plausible consequences of obesity, not yet quantified as CHUJANS-specific rates.

Prognosis is highly variable, even within families. Mildly affected transmitting parents show that adult functioning can be substantially better than in an ascertained child, while larger deletions or additional variants may worsen outcomes. No validated prognostic molecular biomarker exists. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, kampmeier2023phipassociatedchungjansensyndrome pages 2-3)

12. Treatment and current applications

There is no approved PHIP-targeted or disease-modifying treatment. Current real-world care is multidisciplinary and phenotype-directed:

early-intervention services and individualized education;
speech/language, occupational, and physical therapy;
neuropsychological evaluation and behavioral therapy;
standard evidence-based treatment of ADHD, anxiety, aggression, autism-associated needs, constipation, seizures, orthopedic problems, and sleep disorders when present;
longitudinal BMI, blood pressure, glucose/HbA1c, lipids, liver-health, nutrition, activity, and sleep surveillance;
family support and genetic counseling.

Suggested NCIt intervention concepts include Genetic Counseling, Physical Therapy, Occupational Therapy, Speech and Language Therapy, Behavioral Therapy, Nutritional Counseling, and Weight Management; current NCIt codes should be validated before ingestion.

No response rate, syndrome-specific adverse-event profile, pharmacogenomic rule, gene therapy, ASO/siRNA therapy, cell therapy, CRISPR intervention, or targeted melanocortin therapy has been clinically established. Although POMC repression suggests a melanocortin-pathway rationale, extrapolating efficacy of drugs used for other genetic obesities would be premature without CHUJANS trials. (marenne2020exomesequencingidentifies pages 5-6, marenne2020exomesequencingidentifies pages 10-11)

Current implementation: Simons Searchlight, NCT01238250, is a recruiting, international, prospective observational registry with a planned enrollment of 100,000. It collects medical, developmental, learning, behavioral, and annual longitudinal data plus blood/saliva from eligible neurodevelopmental genetic conditions, including PHIP-related disorders. It is not an interventional treatment trial. ClinicalTrials.gov. (NCT01238250 chunk 1, NCT01238250 chunk 2)

13. Prevention

The de novo occurrence of many pathogenic variants means there is no lifestyle-based primary prevention. Relevant prevention is genetic and complication-focused:

Primary/reproductive: genetic counseling, parental testing, prenatal diagnosis, and preimplantation genetic testing when a familial pathogenic variant is known.
Secondary: early molecular diagnosis and prompt developmental, speech, behavioral, and nutritional intervention; cascade testing of relatives.
Tertiary: prevent obesity-related metabolic disease, injuries related to hypotonia/coordination, untreated seizures, constipation complications, and avoidable educational or psychiatric deterioration.

There is no vaccine, antimicrobial prophylaxis, population screening program, or environmental intervention specific to CHUJANS. An apparently de novo result does not reduce recurrence risk to absolute zero because parental germline mosaicism remains possible.

14. Other species and natural disease

No naturally occurring PHIP-related CHUJANS analogue was identified in companion animals, livestock, or wildlife, and no breed-specific VBO annotation is currently justified. There is no zoonotic potential or cross-species transmission. PHIP is evolutionarily conserved, permitting comparative functional modeling, but conservation alone does not establish natural veterinary disease.

15. Model organisms

Mouse

A Phip-null mouse has severe postnatal phenotypes: approximately 40% growth deficit by weaning, hypoglycemia, and death at 4–5 weeks. This supports an essential role in growth and metabolic homeostasis. However, complete knockout is much more severe than typical heterozygous human CHUJANS and does not faithfully reproduce the human obesity phenotype; it is therefore informative for gene function but limited as a therapeutic model. (marenne2020exomesequencingidentifies pages 6-8)

Cellular models

HEK293 POMC-luciferase assays and COS-7 localization experiments currently provide the strongest variant-level functional platform. They demonstrate impaired POMC transcription, altered localization, and dominant-negative behavior for selected variants. Limitations include overexpression, non-neuronal cell backgrounds, and absence of authentic hypothalamic circuitry. (marenne2020exomesequencingidentifies pages 5-6, marenne2020exomesequencingidentifies pages 20-21)

No well-validated PHIP-specific zebrafish, Drosophila, C. elegans, patient-derived iPSC neuron, brain organoid, conditional hypothalamic knockout, or humanized knock-in model was identified in the retrieved evidence. Priority models would include heterozygous LoF and patient-specific knock-in mice, POMC-neuron conditional models, and patient iPSC-derived neurons/hypothalamic organoids.

Research priorities and expert assessment

The authoritative interpretation emerging from current evidence is that CHUJANS is a clinically recognizable but underdiagnosed PHIP dosage disorder with broader expressivity than the original “ID-obesity” label implies. Obesity is important but not obligatory; inherited mildly affected cases mean that trio analysis and careful parental phenotyping are essential. The 2023 investigators specifically recommended including PHIP in diagnostic testing for developmental delay/intellectual disability, behavioral abnormalities, and obesity, and emphasized behavioral and weight follow-up. (kampmeier2023phipassociatedchungjansensyndrome pages 10-11, kampmeier2023phipassociatedchungjansensyndrome pages 1-2)

The highest-priority gaps are: population prevalence; prospective childhood-to-adult natural history; penetrance by variant class; standardized neurobehavioral and quality-of-life outcomes; direct functional studies in human neurons; validation of the methylation signature; and interventional studies addressing obesity and behavior. Registry participation through Simons Searchlight is presently the most concrete implementation for overcoming the small-cohort problem. (NCT01238250 chunk 1, NCT01238250 chunk 2)

References

(kampmeier2023phipassociatedchungjansensyndrome pages 2-3): Antje Kampmeier, Elsa Leitão, Ilaria Parenti, Jasmin Beygo, Christel Depienne, Nuria C Bramswig, Tzung-Chien Hsieh, Alexandra Afenjar, Stefanie Beck-Wödl, Ute Grasshoff, Tobias B Haack, Emilia K Bijlsma, Claudia Ruivenkamp, Eva Lausberg, Miriam Elbracht, Maria K Haanpää, Hannele Koillinen, Uwe Heinrich, Imma Rost, Rami Abou Jamra, Denny Popp, Margarete Koch-Hogrebe, Kevin Rostasy, Vanesa López-González, María José Sanchez-Soler, Catarina Macedo, Ariane Schmetz, Carmen Steinborn, Sabine Weidensee, Hellen Lesmann, Felix Marbach, Pilar Caro, Christian P. Schaaf, Peter Krawitz, Dagmar Wieczorek, Frank J Kaiser, and Alma Kuechler. Phip-associated chung-jansen syndrome: report of 23 new individuals. Frontiers in Cell and Developmental Biology, Jan 2023. URL: https://doi.org/10.3389/fcell.2022.1020609, doi:10.3389/fcell.2022.1020609. This article has 24 citations.
(kampmeier2023phipassociatedchungjansensyndrome pages 1-2): Antje Kampmeier, Elsa Leitão, Ilaria Parenti, Jasmin Beygo, Christel Depienne, Nuria C Bramswig, Tzung-Chien Hsieh, Alexandra Afenjar, Stefanie Beck-Wödl, Ute Grasshoff, Tobias B Haack, Emilia K Bijlsma, Claudia Ruivenkamp, Eva Lausberg, Miriam Elbracht, Maria K Haanpää, Hannele Koillinen, Uwe Heinrich, Imma Rost, Rami Abou Jamra, Denny Popp, Margarete Koch-Hogrebe, Kevin Rostasy, Vanesa López-González, María José Sanchez-Soler, Catarina Macedo, Ariane Schmetz, Carmen Steinborn, Sabine Weidensee, Hellen Lesmann, Felix Marbach, Pilar Caro, Christian P. Schaaf, Peter Krawitz, Dagmar Wieczorek, Frank J Kaiser, and Alma Kuechler. Phip-associated chung-jansen syndrome: report of 23 new individuals. Frontiers in Cell and Developmental Biology, Jan 2023. URL: https://doi.org/10.3389/fcell.2022.1020609, doi:10.3389/fcell.2022.1020609. This article has 24 citations.
(marenne2020exomesequencingidentifies pages 5-6): Gaëlle Marenne, Audrey E. Hendricks, Aliki Perdikari, Rebecca Bounds, Felicity Payne, Julia M. Keogh, Christopher J. Lelliott, Elana Henning, Saad Pathan, Sofie Ashford, Elena G. Bochukova, Vanisha Mistry, Allan Daly, Caroline Hayward, Nicholas J. Wareham, Stephen O’Rahilly, Claudia Langenberg, Eleanor Wheeler, Eleftheria Zeggini, I. Sadaf Farooqi, and Inês Barroso. Exome sequencing identifies genes and gene sets contributing to severe childhood obesity, linking phip variants to repressed pomc transcription. Cell Metabolism, 31:1107-1119.e12, Jun 2020. URL: https://doi.org/10.1016/j.cmet.2020.05.007, doi:10.1016/j.cmet.2020.05.007. This article has 92 citations and is from a highest quality peer-reviewed journal.
(marenne2020exomesequencingidentifies pages 10-11): Gaëlle Marenne, Audrey E. Hendricks, Aliki Perdikari, Rebecca Bounds, Felicity Payne, Julia M. Keogh, Christopher J. Lelliott, Elana Henning, Saad Pathan, Sofie Ashford, Elena G. Bochukova, Vanisha Mistry, Allan Daly, Caroline Hayward, Nicholas J. Wareham, Stephen O’Rahilly, Claudia Langenberg, Eleanor Wheeler, Eleftheria Zeggini, I. Sadaf Farooqi, and Inês Barroso. Exome sequencing identifies genes and gene sets contributing to severe childhood obesity, linking phip variants to repressed pomc transcription. Cell Metabolism, 31:1107-1119.e12, Jun 2020. URL: https://doi.org/10.1016/j.cmet.2020.05.007, doi:10.1016/j.cmet.2020.05.007. This article has 92 citations and is from a highest quality peer-reviewed journal.
(kampmeier2023phipassociatedchungjansensyndrome pages 3-5): Antje Kampmeier, Elsa Leitão, Ilaria Parenti, Jasmin Beygo, Christel Depienne, Nuria C Bramswig, Tzung-Chien Hsieh, Alexandra Afenjar, Stefanie Beck-Wödl, Ute Grasshoff, Tobias B Haack, Emilia K Bijlsma, Claudia Ruivenkamp, Eva Lausberg, Miriam Elbracht, Maria K Haanpää, Hannele Koillinen, Uwe Heinrich, Imma Rost, Rami Abou Jamra, Denny Popp, Margarete Koch-Hogrebe, Kevin Rostasy, Vanesa López-González, María José Sanchez-Soler, Catarina Macedo, Ariane Schmetz, Carmen Steinborn, Sabine Weidensee, Hellen Lesmann, Felix Marbach, Pilar Caro, Christian P. Schaaf, Peter Krawitz, Dagmar Wieczorek, Frank J Kaiser, and Alma Kuechler. Phip-associated chung-jansen syndrome: report of 23 new individuals. Frontiers in Cell and Developmental Biology, Jan 2023. URL: https://doi.org/10.3389/fcell.2022.1020609, doi:10.3389/fcell.2022.1020609. This article has 24 citations.
(kampmeier2023phipassociatedchungjansensyndrome pages 10-11): Antje Kampmeier, Elsa Leitão, Ilaria Parenti, Jasmin Beygo, Christel Depienne, Nuria C Bramswig, Tzung-Chien Hsieh, Alexandra Afenjar, Stefanie Beck-Wödl, Ute Grasshoff, Tobias B Haack, Emilia K Bijlsma, Claudia Ruivenkamp, Eva Lausberg, Miriam Elbracht, Maria K Haanpää, Hannele Koillinen, Uwe Heinrich, Imma Rost, Rami Abou Jamra, Denny Popp, Margarete Koch-Hogrebe, Kevin Rostasy, Vanesa López-González, María José Sanchez-Soler, Catarina Macedo, Ariane Schmetz, Carmen Steinborn, Sabine Weidensee, Hellen Lesmann, Felix Marbach, Pilar Caro, Christian P. Schaaf, Peter Krawitz, Dagmar Wieczorek, Frank J Kaiser, and Alma Kuechler. Phip-associated chung-jansen syndrome: report of 23 new individuals. Frontiers in Cell and Developmental Biology, Jan 2023. URL: https://doi.org/10.3389/fcell.2022.1020609, doi:10.3389/fcell.2022.1020609. This article has 24 citations.
(marenne2020exomesequencingidentifies pages 1-3): Gaëlle Marenne, Audrey E. Hendricks, Aliki Perdikari, Rebecca Bounds, Felicity Payne, Julia M. Keogh, Christopher J. Lelliott, Elana Henning, Saad Pathan, Sofie Ashford, Elena G. Bochukova, Vanisha Mistry, Allan Daly, Caroline Hayward, Nicholas J. Wareham, Stephen O’Rahilly, Claudia Langenberg, Eleanor Wheeler, Eleftheria Zeggini, I. Sadaf Farooqi, and Inês Barroso. Exome sequencing identifies genes and gene sets contributing to severe childhood obesity, linking phip variants to repressed pomc transcription. Cell Metabolism, 31:1107-1119.e12, Jun 2020. URL: https://doi.org/10.1016/j.cmet.2020.05.007, doi:10.1016/j.cmet.2020.05.007. This article has 92 citations and is from a highest quality peer-reviewed journal.
(kampmeier2023phipassociatedchungjansensyndrome pages 12-13): Antje Kampmeier, Elsa Leitão, Ilaria Parenti, Jasmin Beygo, Christel Depienne, Nuria C Bramswig, Tzung-Chien Hsieh, Alexandra Afenjar, Stefanie Beck-Wödl, Ute Grasshoff, Tobias B Haack, Emilia K Bijlsma, Claudia Ruivenkamp, Eva Lausberg, Miriam Elbracht, Maria K Haanpää, Hannele Koillinen, Uwe Heinrich, Imma Rost, Rami Abou Jamra, Denny Popp, Margarete Koch-Hogrebe, Kevin Rostasy, Vanesa López-González, María José Sanchez-Soler, Catarina Macedo, Ariane Schmetz, Carmen Steinborn, Sabine Weidensee, Hellen Lesmann, Felix Marbach, Pilar Caro, Christian P. Schaaf, Peter Krawitz, Dagmar Wieczorek, Frank J Kaiser, and Alma Kuechler. Phip-associated chung-jansen syndrome: report of 23 new individuals. Frontiers in Cell and Developmental Biology, Jan 2023. URL: https://doi.org/10.3389/fcell.2022.1020609, doi:10.3389/fcell.2022.1020609. This article has 24 citations.
(kampmeier2023phipassociatedchungjansensyndrome pages 11-12): Antje Kampmeier, Elsa Leitão, Ilaria Parenti, Jasmin Beygo, Christel Depienne, Nuria C Bramswig, Tzung-Chien Hsieh, Alexandra Afenjar, Stefanie Beck-Wödl, Ute Grasshoff, Tobias B Haack, Emilia K Bijlsma, Claudia Ruivenkamp, Eva Lausberg, Miriam Elbracht, Maria K Haanpää, Hannele Koillinen, Uwe Heinrich, Imma Rost, Rami Abou Jamra, Denny Popp, Margarete Koch-Hogrebe, Kevin Rostasy, Vanesa López-González, María José Sanchez-Soler, Catarina Macedo, Ariane Schmetz, Carmen Steinborn, Sabine Weidensee, Hellen Lesmann, Felix Marbach, Pilar Caro, Christian P. Schaaf, Peter Krawitz, Dagmar Wieczorek, Frank J Kaiser, and Alma Kuechler. Phip-associated chung-jansen syndrome: report of 23 new individuals. Frontiers in Cell and Developmental Biology, Jan 2023. URL: https://doi.org/10.3389/fcell.2022.1020609, doi:10.3389/fcell.2022.1020609. This article has 24 citations.
(NCT01238250 chunk 1): Online Study of People Who Have Genetic Changes and Features of Autism: Simons Searchlight. Simons Searchlight. 2010. ClinicalTrials.gov Identifier: NCT01238250
(NCT01238250 chunk 2): Online Study of People Who Have Genetic Changes and Features of Autism: Simons Searchlight. Simons Searchlight. 2010. ClinicalTrials.gov Identifier: NCT01238250
(kampmeier2023phipassociatedchungjansensyndrome pages 5-5): Antje Kampmeier, Elsa Leitão, Ilaria Parenti, Jasmin Beygo, Christel Depienne, Nuria C Bramswig, Tzung-Chien Hsieh, Alexandra Afenjar, Stefanie Beck-Wödl, Ute Grasshoff, Tobias B Haack, Emilia K Bijlsma, Claudia Ruivenkamp, Eva Lausberg, Miriam Elbracht, Maria K Haanpää, Hannele Koillinen, Uwe Heinrich, Imma Rost, Rami Abou Jamra, Denny Popp, Margarete Koch-Hogrebe, Kevin Rostasy, Vanesa López-González, María José Sanchez-Soler, Catarina Macedo, Ariane Schmetz, Carmen Steinborn, Sabine Weidensee, Hellen Lesmann, Felix Marbach, Pilar Caro, Christian P. Schaaf, Peter Krawitz, Dagmar Wieczorek, Frank J Kaiser, and Alma Kuechler. Phip-associated chung-jansen syndrome: report of 23 new individuals. Frontiers in Cell and Developmental Biology, Jan 2023. URL: https://doi.org/10.3389/fcell.2022.1020609, doi:10.3389/fcell.2022.1020609. This article has 24 citations.
(loid2026anovelphip pages 5-6): Petra Loid, Nina Vuorela, Kirsimari Aaltonen, Juha Kuittinen, and Outi Mäkitie. A novel phip variant in a family with severe early-onset obesity. Hormone research in paediatrics, pages 1-15, Oct 2026. URL: https://doi.org/10.1159/000542205, doi:10.1159/000542205. This article has 5 citations and is from a peer-reviewed journal.
(loid2026anovelphip pages 7-8): Petra Loid, Nina Vuorela, Kirsimari Aaltonen, Juha Kuittinen, and Outi Mäkitie. A novel phip variant in a family with severe early-onset obesity. Hormone research in paediatrics, pages 1-15, Oct 2026. URL: https://doi.org/10.1159/000542205, doi:10.1159/000542205. This article has 5 citations and is from a peer-reviewed journal.
(marenne2020exomesequencingidentifies pages 20-21): Gaëlle Marenne, Audrey E. Hendricks, Aliki Perdikari, Rebecca Bounds, Felicity Payne, Julia M. Keogh, Christopher J. Lelliott, Elana Henning, Saad Pathan, Sofie Ashford, Elena G. Bochukova, Vanisha Mistry, Allan Daly, Caroline Hayward, Nicholas J. Wareham, Stephen O’Rahilly, Claudia Langenberg, Eleanor Wheeler, Eleftheria Zeggini, I. Sadaf Farooqi, and Inês Barroso. Exome sequencing identifies genes and gene sets contributing to severe childhood obesity, linking phip variants to repressed pomc transcription. Cell Metabolism, 31:1107-1119.e12, Jun 2020. URL: https://doi.org/10.1016/j.cmet.2020.05.007, doi:10.1016/j.cmet.2020.05.007. This article has 92 citations and is from a highest quality peer-reviewed journal.
(marenne2020exomesequencingidentifies pages 6-8): Gaëlle Marenne, Audrey E. Hendricks, Aliki Perdikari, Rebecca Bounds, Felicity Payne, Julia M. Keogh, Christopher J. Lelliott, Elana Henning, Saad Pathan, Sofie Ashford, Elena G. Bochukova, Vanisha Mistry, Allan Daly, Caroline Hayward, Nicholas J. Wareham, Stephen O’Rahilly, Claudia Langenberg, Eleanor Wheeler, Eleftheria Zeggini, I. Sadaf Farooqi, and Inês Barroso. Exome sequencing identifies genes and gene sets contributing to severe childhood obesity, linking phip variants to repressed pomc transcription. Cell Metabolism, 31:1107-1119.e12, Jun 2020. URL: https://doi.org/10.1016/j.cmet.2020.05.007, doi:10.1016/j.cmet.2020.05.007. This article has 92 citations and is from a highest quality peer-reviewed journal.

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Chung–Jansen syndrome: disease-characteristics research report

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