Pilarowski-Bjornsson syndrome is a CHD1-related neurodevelopmental disorder associated with heterozygous missense variants and characterized by autism, speech apraxia, developmental delay/intellectual disability, hypotonia, seizures or EEG abnormalities in a subset, and facial dysmorphic features. Current evidence is most consistent with a dominant-negative chromatin-remodeling mechanism.
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name: Pilarowski-Bjornsson syndrome
creation_date: "2026-04-13T22:47:36Z"
updated_date: "2026-04-14T14:35:00Z"
description: >-
Pilarowski-Bjornsson syndrome is a CHD1-related neurodevelopmental disorder
associated with heterozygous missense variants and characterized by autism,
speech apraxia, developmental delay/intellectual disability, hypotonia,
seizures or EEG abnormalities in a subset, and facial dysmorphic features.
Current evidence is most consistent with a dominant-negative
chromatin-remodeling mechanism.
category: Mendelian
parents:
- hereditary disease
- neurodevelopmental disorder
disease_term:
preferred_term: Pilarowski-Bjornsson syndrome
term:
id: MONDO:0060568
label: Pilarowski-Bjornsson syndrome
inheritance:
- name: Autosomal dominant inheritance
description: >-
Pilarowski-Bjornsson syndrome is associated with heterozygous CHD1 missense
variants, including recurrent de novo events, consistent with autosomal
dominant inheritance.
inheritance_term:
preferred_term: Autosomal dominant inheritance
term:
id: HP:0000006
label: Autosomal dominant inheritance
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Importantly, three of these variants occurred de novo."
explanation: This supports autosomal dominant disease through heterozygous de novo CHD1 variants.
mechanistic_hypotheses:
- hypothesis_group_id: chd1_missense_dominant_negative_model
hypothesis_label: CHD1 Missense Dominant-Negative Model
status: CANONICAL
description: >-
The core human disease model is heterozygous CHD1 missense variation, often
de novo, producing neurodevelopmental disability through a dominant-negative
effect rather than simple haploinsufficiency.
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Our results suggest that variants in CHD1 can lead to diverse phenotypic outcomes; however, the neurodevelopmental phenotype appears to be limited to patients with missense variants, which is compatible with a dominant negative mechanism of disease.
explanation: >-
The founding cohort directly frames missense CHD1 variants as a
dominant-negative neurodevelopmental disease model.
- hypothesis_group_id: chd1_closed_chromatin_fibroblast_model
hypothesis_label: CHD1 Closed-Chromatin Fibroblast Model
status: EMERGING
description: >-
Fibroblast assays from an affected subject support increased H3K27me3 and a
closed-chromatin state downstream of CHD1 missense dysfunction; this is
separated from the patient genetic evidence because it is cell-assay based.
notes: >-
Classified as emerging because the direct assay evidence is from cultured
fibroblasts from one subject rather than neural tissue.
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Finally, we demonstrate increased levels of the closed chromatin modification H3K27me3 in fibroblasts from a subject carrying a de novo variant in CHD1.
explanation: >-
This distinguishes the cell-assay chromatin evidence from the human
clinical genetic evidence.
- hypothesis_group_id: chd1_craniofacial_neural_crest_model
hypothesis_label: CHD1 Craniofacial Neural-Crest Model
status: EMERGING
description: >-
Xenopus Chd1 knockdown and CRISPR experiments support a model in which CHD1
disruption impairs cranial neural crest development, jaw cartilage
morphology, and cell survival during craniofacial development.
evidence:
- reference: PMID:32918369
reference_title: "Using an aquatic model, Xenopus laevis, to uncover the role of chromodomain 1 in craniofacial disorders."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
Further analysis indicated that embryos deficient in Chd1 had defects in cranial neural crest development and jaw cartilage morphology.
explanation: >-
Xenopus model data support a craniofacial developmental mechanism that is
distinct from patient-only phenotype assertion.
- hypothesis_group_id: androgen_modulated_sex_dimorphism_model
hypothesis_label: Androgen-Modulated Sex-Dimorphism Model
status: EMERGING
description: >-
A 2025 preprint proposes androgen-regulated sex-specific penetrance and
expressivity in Pilarowski-Bjornsson syndrome, with cohort, mouse-model, and
population-variant evidence.
notes: >-
Treated cautiously as preprint evidence until peer-reviewed replication or
publication clarifies clinical interpretation.
evidence:
- reference: PMID:40385454
reference_title: Androgens mediate sexual dimorphism in Pilarowski-Bjornsson Syndrome.
supports: PARTIAL
evidence_source: OTHER
snippet: >-
Here, we describe the clinical and genetic characteristics of the largest PILBOS cohort to date, showing that both sexes can exhibit PILBOS features, although males are overrepresented.
explanation: >-
The preprint supports a sex-distribution hypothesis in a larger cohort but
remains provisional.
- reference: PMID:40385454
reference_title: Androgens mediate sexual dimorphism in Pilarowski-Bjornsson Syndrome.
supports: PARTIAL
evidence_source: MODEL_ORGANISM
snippet: >-
Orchiectomy unmasks a growth deficiency phenotype in male Chd1 R616Q/+ mice, while testosterone rescues the phenotype in females, implicating androgens in phenotype modulation.
explanation: >-
Mouse intervention data support androgen modulation as an experimental
mechanism, not an established human treatment.
pathophysiology:
- name: CHD1 missense dysfunction
description: >-
Pilarowski-Bjornsson syndrome is caused by heterozygous CHD1 missense
variants affecting a chromatin remodeler required for normal epigenetic
regulation.
gene:
preferred_term: CHD1
description: Chromodomain helicase DNA binding protein 1 chromatin remodeler.
term:
id: hgnc:1915
label: CHD1
genes:
- preferred_term: CHD1
term:
id: hgnc:1915
label: CHD1
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features."
explanation: This directly supports CHD1 missense variants as the disease-defining genetic lesion.
downstream:
- target: Altered chromatin state
description: CHD1 dysfunction perturbs chromatin remodeling and epigenetic state.
hypothesis_groups:
- chd1_closed_chromatin_fibroblast_model
- target: Neurodevelopmental impairment
description: Epigenetic dysregulation disrupts normal neurodevelopmental trajectories.
hypothesis_groups:
- chd1_missense_dominant_negative_model
- target: Cranial neural crest and jaw cartilage disruption
description: CHD1 disruption can impair cranial neural crest and jaw cartilage development in model systems.
hypothesis_groups:
- chd1_craniofacial_neural_crest_model
- name: Altered chromatin state
description: >-
CHD1 missense dysfunction is associated in cultured fibroblasts with
increased levels of the closed chromatin mark H3K27me3, supporting but not
alone proving an epigenetic disease mechanism.
biological_processes:
- preferred_term: chromatin organization
modifier: ABNORMAL
term:
id: GO:0006325
label: chromatin organization
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: IN_VITRO
snippet: "Finally, we demonstrate increased levels of the closed chromatin modification H3K27me3 in fibroblasts from a subject carrying a de novo variant in CHD1."
explanation: This directly supports epigenetic dysregulation and altered chromatin state in the disorder.
downstream:
- target: Neurodevelopmental impairment
description: Altered chromatin regulation contributes to downstream neurodevelopmental dysfunction.
hypothesis_groups:
- chd1_closed_chromatin_fibroblast_model
- name: Neurodevelopmental impairment
description: >-
Downstream neurodevelopmental dysfunction produces the core autism, speech,
and developmental phenotype of Pilarowski-Bjornsson syndrome.
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features."
explanation: This directly supports neurodevelopmental impairment as the major downstream disease consequence.
downstream:
- target: Global developmental delay
description: Neurodevelopmental dysfunction causes developmental delay.
- target: Autism
description: Altered neurodevelopment contributes to autism phenotype.
- target: Speech apraxia
description: Neurodevelopmental dysfunction contributes to speech motor planning deficits.
- name: Cranial neural crest and jaw cartilage disruption
description: >-
Reduced Chd1 function in Xenopus disrupts cranial neural crest development
and jaw cartilage morphology, providing model-organism support for
craniofacial features in CHD1-related disease.
evidence:
- reference: PMID:32918369
reference_title: "Using an aquatic model, Xenopus laevis, to uncover the role of chromodomain 1 in craniofacial disorders."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
Further analysis indicated that embryos deficient in Chd1 had defects in cranial neural crest development and jaw cartilage morphology.
explanation: >-
This supports a cranial-neural-crest model for CHD1-associated
craniofacial abnormalities.
downstream:
- target: Abnormal facial shape
description: Cranial neural crest and cartilage disruption may contribute to dysmorphic craniofacial morphology.
hypothesis_groups:
- chd1_craniofacial_neural_crest_model
phenotypes:
- name: Global developmental delay
category: Neurodevelopmental
diagnostic: true
description: Developmental delay is one of the core presenting features of Pilarowski-Bjornsson syndrome.
phenotype_term:
preferred_term: Global developmental delay
term:
id: HP:0001263
label: Global developmental delay
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features."
explanation: This directly supports developmental delay in the syndrome.
- name: Intellectual disability
category: Neurodevelopmental
description: Intellectual disability is included in the founding summary of the CHD1-related neurodevelopmental disorder.
phenotype_term:
preferred_term: Intellectual disability
term:
id: HP:0001249
label: Intellectual disability
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In summary, our data show that missense variants in the chromatin remodeler CHD1 are associated with a novel neurodevelopmental disorder with intellectual disability, autism, seizures, speech apraxia, and dysmorphic features.
explanation: >-
The founding cohort summary directly includes intellectual disability in
the CHD1-associated disorder.
- name: Hypotonia
category: Neurologic
description: Hypotonia was reported across the clinically characterized founding patients.
phenotype_term:
preferred_term: Hypotonia
term:
id: HP:0001252
label: Hypotonia
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
All five patients had developmental delay and hypotonia, all are female and some had epileptiform abnormalities on an EEG (Table 1).
explanation: >-
This directly supports hypotonia as part of the clinically characterized
CHD1 missense cohort.
- name: Autism
category: Neurodevelopmental
description: Autism is a frequent neurobehavioral feature in the original CHD1 missense cohort.
phenotype_term:
preferred_term: Autism
term:
id: HP:0000717
label: Autism
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features."
explanation: This directly supports autism in the syndrome phenotype.
- name: Speech apraxia
category: Neurodevelopmental
description: Speech apraxia is a distinctive and recurring neurodevelopmental feature.
phenotype_term:
preferred_term: Speech apraxia
term:
id: HP:0011098
label: Speech apraxia
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features."
explanation: This directly supports speech apraxia in Pilarowski-Bjornsson syndrome.
- name: Seizure
category: Neurologic
description: Seizures are reported in the founding CHD1-associated neurodevelopmental disorder summary.
phenotype_term:
preferred_term: Seizure
term:
id: HP:0001250
label: Seizure
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In summary, our data show that missense variants in the chromatin remodeler CHD1 are associated with a novel neurodevelopmental disorder with intellectual disability, autism, seizures, speech apraxia, and dysmorphic features.
explanation: >-
The founding summary includes seizures among the associated clinical
features.
- name: EEG abnormality
category: Neurologic
description: Epileptiform EEG abnormalities were present in a subset of the clinically described patients.
phenotype_term:
preferred_term: EEG abnormality
term:
id: HP:0002353
label: EEG abnormality
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
All five patients had developmental delay and hypotonia, all are female and some had epileptiform abnormalities on an EEG (Table 1).
explanation: >-
The founding cohort reports epileptiform EEG abnormalities in a subset.
- name: Abnormal facial shape
category: Craniofacial
description: Facial dysmorphic features are part of the syndrome gestalt.
phenotype_term:
preferred_term: facial dysmorphic features
term:
id: HP:0001999
label: Abnormal facial shape
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features."
explanation: This directly supports dysmorphic facial features as part of the syndrome phenotype.
- name: Pointed chin
category: Craniofacial
description: Pointed chin is one of the more specific dysmorphic features reported in a subset.
phenotype_term:
preferred_term: Pointed chin
term:
id: HP:0000307
label: Pointed chin
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
A subset of patients had dysmorphic features including a pointed chin, frontal bossing and arched eyebrows (Figure 1B).
explanation: This supports pointed chin as a specific dysmorphic feature.
- name: Frontal bossing
category: Craniofacial
description: Frontal bossing is one of the more specific dysmorphic features reported in a subset.
phenotype_term:
preferred_term: Frontal bossing
term:
id: HP:0002007
label: Frontal bossing
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
A subset of patients had dysmorphic features including a pointed chin, frontal bossing and arched eyebrows (Figure 1B).
explanation: This supports frontal bossing as a specific dysmorphic feature.
- name: Highly arched eyebrow
category: Craniofacial
description: Arched eyebrows are one of the more specific dysmorphic features reported in a subset.
phenotype_term:
preferred_term: Highly arched eyebrow
term:
id: HP:0002553
label: Highly arched eyebrow
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
A subset of patients had dysmorphic features including a pointed chin, frontal bossing and arched eyebrows (Figure 1B).
explanation: This supports arched eyebrows as a specific dysmorphic feature.
genetic:
- name: CHD1
association: Causal heterozygous missense variant
notes: >-
The neurodevelopmental phenotype appears restricted to CHD1 missense
variants, consistent with a dominant-negative disease mechanism.
evidence:
- reference: DOI:10.1136/jmedgenet-2017-104759
reference_title: "Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability"
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Our results suggest that variants in CHD1 can lead to diverse phenotypic outcomes; however, the neurodevelopmental phenotype appears to be limited to patients with missense variants, which is compatible with a dominant negative mechanism of disease."
explanation: This directly supports CHD1 missense causality and the likely dominant-negative mechanism.
- reference: PMID:38174187
reference_title: A Saudi Girl With Co-occurring CHD1 (Pilarowski-Bjornsson Syndrome) and ASH1L Gene Variants.
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
Notably, this case is unique due to the coexisting presence of an absent, small, and homeotic disks protein 1 homolog like a histone lysine methyltransferase (ASH1L) variant and developmental dissociation.
explanation: >-
This newer case supports additional CHD1 reporting but is treated
cautiously because a coexisting ASH1L variant may modify the phenotype.
treatments:
- name: Genetic counseling
description: >-
Genetic counseling should address dominant CHD1 missense causality, de novo
occurrence, recurrence-risk assessment, and the current uncertainty around
penetrance and sex-modified expressivity.
treatment_term:
preferred_term: genetic counseling
term:
id: MAXO:0000079
label: genetic counseling
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Importantly, three of these variants occurred de novo.
explanation: >-
De novo heterozygous CHD1 variants support genetic counseling for
recurrence risk and family testing.
- name: Developmental therapy and rehabilitation
description: >-
Developmental, occupational, and physical-therapy supports should be
individualized for developmental delay, intellectual disability, and
hypotonia.
treatment_term:
preferred_term: occupational therapy
term:
id: MAXO:0001351
label: occupational therapy
target_phenotypes:
- preferred_term: Global developmental delay
term:
id: HP:0001263
label: Global developmental delay
- preferred_term: Intellectual disability
term:
id: HP:0001249
label: Intellectual disability
- preferred_term: Hypotonia
term:
id: HP:0001252
label: Hypotonia
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
All five patients had developmental delay and hypotonia, all are female and some had epileptiform abnormalities on an EEG (Table 1).
explanation: >-
Developmental delay and hypotonia support rehabilitation-focused
management, although the citation is phenotype rather than treatment-trial
evidence.
- name: Speech therapy
description: >-
Speech-language therapy is relevant for speech apraxia and related
communication needs.
treatment_term:
preferred_term: speech therapy
term:
id: MAXO:0000930
label: speech therapy
target_phenotypes:
- preferred_term: Speech apraxia
term:
id: HP:0011098
label: Speech apraxia
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
Four of our subjects with CHD1 mutations carried a diagnosis of speech apraxia.
explanation: >-
Speech apraxia supports speech-language therapy as symptomatic supportive
management.
- name: Behavioral and autism support
description: >-
Behavioral counseling and autism-focused supports should be individualized
for social communication and behavioral needs.
treatment_term:
preferred_term: behavioral counseling
term:
id: MAXO:0000077
label: behavioral counseling
target_phenotypes:
- preferred_term: Autism
term:
id: HP:0000717
label: Autism
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
Three of these patients also received a diagnosis of autism, although one (Subject 1) no longer carries this diagnosis.
explanation: >-
Autism diagnoses in the cohort support autism-focused behavioral support,
while the evidence is not a treatment-efficacy study.
- name: Seizure-directed neurologic management
description: >-
Neurology evaluation and seizure-directed pharmacotherapy should be guided
by clinical seizure history and EEG findings where present.
treatment_term:
preferred_term: pharmacotherapy
term:
id: MAXO:0000058
label: pharmacotherapy
target_phenotypes:
- preferred_term: Seizure
term:
id: HP:0001250
label: Seizure
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
In summary, our data show that missense variants in the chromatin remodeler CHD1 are associated with a novel neurodevelopmental disorder with intellectual disability, autism, seizures, speech apraxia, and dysmorphic features.
explanation: >-
Seizures in the clinical spectrum support seizure-directed management when
clinically indicated; this is not a disease-specific medication trial.
diagnosis:
- name: CHD1 molecular genetic testing
presence: Identification of a pathogenic heterozygous CHD1 missense variant confirms the diagnosis.
description: Molecular testing of CHD1 is the key confirmatory diagnostic procedure for Pilarowski-Bjornsson syndrome.
diagnosis_term:
preferred_term: molecular genetic testing
term:
id: MAXO:0000533
label: molecular genetic testing
qualifiers:
- predicate:
preferred_term: has participant
term:
id: RO:0000057
label: has participant
value:
preferred_term: CHD1
term:
id: hgnc:1915
label: CHD1
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features.
explanation: >-
The defining patient cohort supports CHD1 sequencing as confirmatory
molecular diagnosis.
- name: Electroencephalography
diagnosis_term:
preferred_term: electroencephalography
term:
id: MAXO:0000932
label: electroencephalography
description: >-
EEG evaluation is relevant when seizures, spells, regression, or other
paroxysmal neurologic concerns are present because epileptiform EEG
abnormalities occur in a subset.
results: Epileptiform EEG abnormalities support seizure-focused clinical management.
evidence:
- reference: PMID:28866611
reference_title: Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
All five patients had developmental delay and hypotonia, all are female and some had epileptiform abnormalities on an EEG (Table 1).
explanation: >-
The founding cohort supports EEG assessment when clinically indicated.
differential_diagnoses: []
animal_models:
- species: Xenopus laevis
genotype: Chd1 knockdown or mosaic CRISPR/Cas9-mediated mutagenesis
description: >-
Xenopus Chd1 reduction models craniofacial developmental disruption through
cranial neural crest defects, abnormal jaw cartilage morphology, increased
apoptosis in the developing head, and interaction with retinoic-acid
signaling.
associated_phenotypes:
- Craniofacial defects
- Cranial neural crest defects
- Jaw cartilage morphology defects
evidence:
- reference: PMID:32918369
reference_title: "Using an aquatic model, Xenopus laevis, to uncover the role of chromodomain 1 in craniofacial disorders."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
Protein and gene knockdown techniques in Xenopus, including antisense oligos and mosaic Crispr/Cas9-mediated mutagenesis, recapitulated the craniofacial defects observed in humans.
explanation: >-
This establishes the Xenopus Chd1 perturbation model for craniofacial
features relevant to CHD1-associated disorders.
clinical_trials: []
datasets: []
notes: >-
Asta deep research was completed for this disorder. Current curation anchors
the clinical syndrome to the founding CHD1 missense cohort, treats the
co-occurring CHD1/ASH1L case as phenotype-boundary caution rather than clean
expansion, and records the androgen/sex-dimorphism report as emerging preprint
evidence rather than established clinical management.
This report is retrieval-only and is generated directly from Asta results.
search_papers_by_relevance with snippet_search.