Adams-Oliver syndrome (AOS) is a rare congenital disorder characterized by the combination of aplasia cutis congenita (ACC) of the scalp vertex and terminal transverse limb defects (TTLD) ranging from nail dystrophy to complete digit or limb absence. Additional features include congenital heart defects, cutis marmorata telangiectatica congenita, and pulmonary arterial hypertension. AOS is genetically heterogeneous with both autosomal dominant (NOTCH1, DLL4, RBPJ, ARHGAP31) and autosomal recessive (DOCK6, EOGT) forms. RBPJ mutations act through a dominant-negative mechanism. The pathophysiology converges on disrupted Notch signaling and vascular development, affecting skin, limb, and cardiovascular morphogenesis.
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name: Adams-Oliver Syndrome
creation_date: '2026-04-22T00:00:00Z'
updated_date: '2026-04-26T22:34:05Z'
category: Genetic
synonyms:
- AOS
- Aplasia cutis congenita with terminal transverse limb defects
description: >
Adams-Oliver syndrome (AOS) is a rare congenital disorder characterized by
the combination of aplasia cutis congenita (ACC) of the scalp vertex and
terminal transverse limb defects (TTLD) ranging from nail dystrophy to
complete digit or limb absence. Additional features include congenital heart
defects, cutis marmorata telangiectatica congenita, and pulmonary arterial
hypertension. AOS is genetically heterogeneous with both autosomal dominant
(NOTCH1, DLL4, RBPJ, ARHGAP31) and autosomal recessive (DOCK6, EOGT) forms.
RBPJ mutations act through a dominant-negative mechanism.
The pathophysiology converges on disrupted Notch signaling and vascular
development, affecting skin, limb, and cardiovascular morphogenesis.
disease_term:
preferred_term: Adams-Oliver syndrome
term:
id: MONDO:0007034
label: Adams-Oliver syndrome
parents:
- Ectodermal dysplasia
- Congenital limb malformation
- Congenital heart disease
has_subtypes:
- name: AOS1
display_name: AOS1 (ARHGAP31, autosomal dominant)
description: >
Autosomal dominant form caused by gain-of-function mutations in ARHGAP31,
encoding a Rho GTPase-activating protein. The mutant protein shows
constitutive Cdc42/Rac1 GAP activity, disrupting cytoskeletal dynamics
and cell migration.
evidence:
- reference: PMID:21565291
reference_title: "Gain-of-function mutations of ARHGAP31, a Cdc42/Rac1 GTPase regulator, cause syndromic cutis aplasia and limb anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Candidate-gene- and exome-based sequencing led to the identification of independent premature truncating mutations in the terminal exon of the Rho GTPase-activating protein 31 gene, ARHGAP31, which encodes a Cdc42/Rac1 regulatory protein."
explanation: Original identification of ARHGAP31 as causative for autosomal dominant AOS.
- name: AOS2
display_name: AOS2 (DOCK6, autosomal recessive)
description: >
Autosomal recessive form caused by loss-of-function mutations in DOCK6,
a guanine nucleotide exchange factor for Cdc42 and Rac1. Loss of DOCK6
function impairs cytoskeletal regulation and cell migration.
evidence:
- reference: PMID:21820096
reference_title: "Recessive mutations in DOCK6, encoding the guanidine nucleotide exchange factor DOCK6, lead to abnormal actin cytoskeleton organization and Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "we combined autozygome analysis with exome sequencing to identify a homozygous truncating mutation in dedicator of cytokinesis 6 gene (DOCK6) which encodes an atypical guanidine exchange factor (GEF) known to activate two members of the Rho GTPase family: Cdc42 and Rac1."
explanation: Original identification of DOCK6 as causative for autosomal recessive AOS.
- name: AOS3
display_name: AOS3 (RBPJ, autosomal dominant)
description: >
Autosomal dominant form caused by dominant-negative mutations in RBPJ,
the central transcriptional mediator of canonical Notch signaling.
Mutant RBPJ retains cofactor binding but has impaired DNA binding,
sequestering Notch pathway cofactors from target gene promoters.
evidence:
- reference: PMID:22883147
reference_title: "RBPJ mutations identified in two families affected by Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "we identified two unique mutations in recombination signal binding protein for immunoglobulin kappa J (RBPJ) in two independent families affected by Adams-Oliver syndrome (AOS)"
explanation: Original identification of RBPJ mutations in AOS families.
- name: AOS4
display_name: AOS4 (EOGT, autosomal recessive)
description: >
Autosomal recessive form caused by loss-of-function mutations in EOGT,
which encodes an EGF-domain-specific O-linked N-acetylglucosamine
transferase that modifies Notch receptors.
evidence:
- reference: PMID:23522784
reference_title: "Mutations in EOGT confirm the genetic heterogeneity of autosomal-recessive Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "exome sequencing in one family revealed one missense mutation in EOGT (C3orf64), and subsequent targeted sequencing of this gene revealed a homozygous missense mutation and a homozygous frameshift deletion mutation in the other two families."
explanation: Original identification of EOGT mutations in autosomal recessive AOS.
- name: AOS5
display_name: AOS5 (NOTCH1, autosomal dominant)
description: >
Autosomal dominant form caused by loss-of-function mutations in NOTCH1.
This is the most common genetic subtype. NOTCH1 haploinsufficiency
directly impairs Notch signaling in vascular and skeletal development.
evidence:
- reference: PMID:25963545
reference_title: "Haploinsufficiency of the NOTCH1 Receptor as a Cause of Adams-Oliver Syndrome With Variable Cardiac Anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "This report establishes NOTCH1 mutation as the primary cause of AOS, accounting for 17% of cases in our cohort, and an important genetic factor in AOS with associated cardiovascular complications."
explanation: Demonstrates NOTCH1 as the most common cause of AOS with cardiac associations.
- name: AOS6
display_name: AOS6 (DLL4, autosomal dominant)
description: >
Autosomal dominant form caused by loss-of-function mutations in DLL4,
a Notch ligand critical for angiogenesis and vascular patterning.
evidence:
- reference: PMID:26299364
reference_title: "Heterozygous Loss-of-Function Mutations in DLL4 Cause Adams-Oliver Syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "nine heterozygous mutations in DLL4 were identified, including two nonsense and seven missense variants"
explanation: Original identification of DLL4 mutations as a cause of autosomal dominant AOS.
pathophysiology:
- name: Disrupted Notch Signaling
description: >
The core pathogenic mechanism in AOS involves disruption of the Notch
signaling pathway. NOTCH1 (AOS5), DLL4 (AOS6), RBPJ (AOS3), and EOGT
(AOS4) are direct components or modifiers of Notch signaling. NOTCH1
haploinsufficiency reduces Notch pathway activation in endothelial cells,
impairing angiogenesis and vascular development. DLL4 is a key Notch
ligand in tip cell selection during sprouting angiogenesis. RBPJ is
the obligate transcriptional effector of canonical Notch signaling.
EOGT O-GlcNAcylates Notch EGF repeats, modulating receptor-ligand
interactions.
cell_types:
- preferred_term: endothelial cell
term:
id: CL:0000115
label: endothelial cell
biological_processes:
- preferred_term: Notch signaling pathway
term:
id: GO:0007219
label: Notch signaling pathway
- preferred_term: angiogenesis
term:
id: GO:0001525
label: angiogenesis
- preferred_term: sprouting angiogenesis
term:
id: GO:0002040
label: sprouting angiogenesis
downstream:
- target: Impaired Vascular Development
- target: Defective Skeletal Morphogenesis
- target: Cardiac Outflow Tract Maldevelopment
evidence:
- reference: PMID:25963545
reference_title: "Haploinsufficiency of the NOTCH1 Receptor as a Cause of Adams-Oliver Syndrome With Variable Cardiac Anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "NOTCH1 expression is down-regulated in AOS subjects harboring NOTCH1 mutation in vivo"
explanation: Demonstrates that NOTCH1 mutations lead to haploinsufficiency and reduced Notch signaling.
- reference: PMID:41055965
reference_title: "Defective Notch1 signaling in endothelial cells drives pathogenesis in a mouse model of Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "expression of the Rbpj AOS allele in endothelial cells is both necessary and sufficient to cause lethality and cardiovascular defects"
explanation: Mouse model demonstrates that defective Notch signaling specifically in endothelial cells drives AOS pathogenesis.
- reference: PMID:22883147
reference_title: "RBPJ mutations identified in two families affected by Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "These identified mutations link RBPJ, the primary transcriptional regulator for the Notch pathway, with AOS, a human genetic disorder."
explanation: RBPJ mutations confirm the central role of Notch signaling in AOS.
- name: Rho GTPase Signaling Dysregulation
description: >
ARHGAP31 (AOS1) and DOCK6 (AOS2) act through the Rho GTPase pathway.
ARHGAP31 gain-of-function mutations produce a constitutively active
C-terminal truncation that hyperactivates GAP activity toward Cdc42
and Rac1, reducing their active GTP-bound forms. Conversely, DOCK6
loss-of-function reduces GEF activity toward Cdc42 and Rac1. Both
mechanisms converge on reduced Cdc42/Rac1 activity, impairing
cytoskeletal dynamics, cell migration, and cell survival during
limb and skin development.
cell_types:
- preferred_term: mesenchymal stem cell
term:
id: CL:0000134
label: mesenchymal stem cell
biological_processes:
- preferred_term: Rho protein signal transduction
term:
id: GO:0007266
label: Rho protein signal transduction
- preferred_term: cell migration
term:
id: GO:0016477
label: cell migration
downstream:
- target: Impaired Vascular Development
- target: Defective Skeletal Morphogenesis
evidence:
- reference: PMID:21565291
reference_title: "Gain-of-function mutations of ARHGAP31, a Cdc42/Rac1 GTPase regulator, cause syndromic cutis aplasia and limb anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Constitutively active ARHGAP31 mutations result in a loss of available active Cdc42 and consequently disrupt actin cytoskeletal structures."
explanation: Demonstrates the gain-of-function mechanism of ARHGAP31 mutations disrupting Rho GTPase signaling.
- reference: PMID:21820096
reference_title: "Recessive mutations in DOCK6, encoding the guanidine nucleotide exchange factor DOCK6, lead to abnormal actin cytoskeleton organization and Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Consistent with the established role of Cdc42 and Rac1 in the organization of the actin cytoskeleton, we demonstrate a cellular phenotype typical of a defective actin cytoskeleton in patient cells."
explanation: Confirms DOCK6 loss-of-function disrupts actin cytoskeleton via reduced Cdc42/Rac1 activity.
- name: Impaired Vascular Development
description: >
Disrupted Notch and Rho GTPase signaling converge on impaired vascular
morphogenesis. Defective angiogenesis leads to vascular insufficiency
in the developing scalp, limbs, and potentially other organs. This
vascular disruption hypothesis explains the pattern of terminal defects
(scalp vertex, distal limbs) as watershed areas vulnerable to ischemic
injury during development. Cutis marmorata telangiectatica congenita
and pulmonary arterial hypertension reflect ongoing vascular dysfunction.
cell_types:
- preferred_term: blood vessel endothelial cell
term:
id: CL:0000071
label: blood vessel endothelial cell
biological_processes:
- preferred_term: vasculogenesis
term:
id: GO:0001570
label: vasculogenesis
- preferred_term: angiogenesis
term:
id: GO:0001525
label: angiogenesis
evidence:
- reference: PMID:25132448
reference_title: "Mutations in NOTCH1 cause Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "We propose that the limb and scalp defects might also be due to a vasculopathy in NOTCH1-related AOS."
explanation: Proposes the vascular disruption hypothesis for limb and scalp defects in AOS.
- reference: PMID:41055965
reference_title: "Defective Notch1 signaling in endothelial cells drives pathogenesis in a mouse model of Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "reduced Notch1 signaling in the vasculature is a key driver of pathogenesis in this AOS mouse model"
explanation: Direct evidence from conditional mouse genetics that vascular-specific Notch signaling defects drive AOS.
- name: Defective Skeletal Morphogenesis
description: >
Impaired osteoblast differentiation and skeletal patterning lead to
skull ossification defects and terminal limb deficiencies. The calvarial
defects reflect disrupted intramembranous ossification of the skull vault,
while limb defects represent failure of distal limb patterning and growth.
cell_types:
- preferred_term: osteoblast
term:
id: CL:0000062
label: osteoblast
biological_processes:
- preferred_term: osteoblast differentiation
term:
id: GO:0001649
label: osteoblast differentiation
evidence:
- reference: PMID:21565291
reference_title: "Gain-of-function mutations of ARHGAP31, a Cdc42/Rac1 GTPase regulator, cause syndromic cutis aplasia and limb anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Arhgap31 expression in the mouse is substantially restricted to the terminal limb buds and craniofacial processes during early development; these locations closely mirror the sites of impaired organogenesis that characterize this syndrome."
explanation: Expression pattern of ARHGAP31 mirrors the anatomical sites of skeletal defects in AOS.
- name: Cardiac Outflow Tract Maldevelopment
description: >
DLL4-mediated Notch signaling is required for second heart field (SHF)
progenitor cell proliferation. Loss of DLL4 depletes the SHF progenitor
pool, leading to underdevelopment of the right ventricle and outflow
tract malalignment. This mechanism explains the congenital heart defects
observed in approximately 23% of AOS patients.
cell_types:
- preferred_term: second heart field progenitor cell
term:
id: CL:0000513
label: cardiac muscle myoblast
biological_processes:
- preferred_term: Notch signaling pathway
term:
id: GO:0007219
label: Notch signaling pathway
evidence:
- reference: PMID:33899511
reference_title: "Murine Model of Cardiac Defects Observed in Adams-Oliver Syndrome Driven by Delta-Like Ligand-4 Haploinsufficiency."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "Dll4-mediated Notch signaling is critically required for SHF proliferation such that Dll4 knockout results in a 33% reduction in proliferation and a fourfold increase in apoptosis in SHF cells, leading to a 56% decline in the size of the SHF progenitor pool."
explanation: Mouse model demonstrates the mechanism by which DLL4 haploinsufficiency causes cardiac defects in AOS.
phenotypes:
- category: Dermatological
name: Aplasia Cutis Congenita of the Scalp
frequency: VERY_FREQUENT
description: >
Congenital absence of skin, typically at the vertex of the scalp.
Ranges from small, well-circumscribed defects to large areas of absent
skin with exposed skull or dura. This is a hallmark feature of AOS.
phenotype_term:
preferred_term: Aplasia cutis congenita of scalp
term:
id: HP:0007385
label: Aplasia cutis congenita of scalp
evidence:
- reference: PMID:28160419
reference_title: "Adams-Oliver syndrome review of the literature: Refining the diagnostic phenotype."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The Adams-Oliver syndrome (AOS) is defined as aplasia cutis congenita (ACC) with transverse terminal limb defects (TTLD)."
explanation: ACC is a defining feature of AOS.
- category: Musculoskeletal
name: Terminal Transverse Limb Defects
frequency: VERY_FREQUENT
description: >
Congenital terminal transverse limb defects ranging from nail
dystrophy and short distal phalanges to oligodactyly or complete
absence of digits, hands, or feet. Lower limbs are more frequently
affected than upper limbs.
phenotype_term:
preferred_term: Terminal transverse limb defect
term:
id: HP:6000818
label: Transverse terminal limb defect
evidence:
- reference: PMID:28160419
reference_title: "Adams-Oliver syndrome review of the literature: Refining the diagnostic phenotype."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The Adams-Oliver syndrome (AOS) is defined as aplasia cutis congenita (ACC) with transverse terminal limb defects (TTLD)."
explanation: TTLD is a defining feature of AOS.
- category: Musculoskeletal
name: Calvarial Skull Defect
frequency: FREQUENT
description: >
Defects in skull ossification overlying the aplasia cutis, reflecting
impaired intramembranous ossification. May range from thinning to
complete absence of calvarium.
phenotype_term:
preferred_term: Calvarial skull defect
term:
id: HP:0001362
label: Calvarial skull defect
evidence:
- reference: PMID:25963545
reference_title: "Haploinsufficiency of the NOTCH1 Receptor as a Cause of Adams-Oliver Syndrome With Variable Cardiac Anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Patient 3-III:1 was born with a large area of scalp ACC with an underlying calvarial defect and shortened distal phalanges of the toes"
explanation: Clinical documentation of calvarial skull defects accompanying aplasia cutis in AOS patients.
- category: Cardiovascular
name: Congenital Heart Defects
frequency: OCCASIONAL
description: >
Various structural heart defects reported in AOS, most commonly
ventricular septal defects, tetralogy of Fallot, and coarctation
of the aorta. Observed in approximately 23% of AOS cases overall,
but up to 47% in NOTCH1-positive cases.
phenotype_term:
preferred_term: Congenital heart defect
term:
id: HP:0001627
label: Abnormal heart morphology
evidence:
- reference: PMID:28160419
reference_title: "Adams-Oliver syndrome review of the literature: Refining the diagnostic phenotype."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "the most commonly associated anomalies included a wide variety of central nervous system (CNS) anomalies and congenital heart defects each seen in 23%."
explanation: Large literature review establishing 23% frequency of congenital heart defects in AOS.
- reference: PMID:25963545
reference_title: "Haploinsufficiency of the NOTCH1 Receptor as a Cause of Adams-Oliver Syndrome With Variable Cardiac Anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "cardiovascular anomalies were identified in 47% (8/17) of all affected variant carriers, thereby indicating that NOTCH1 variants may represent a distinct subtype of AOS associated with cardiac malformations."
explanation: NOTCH1-related AOS shows particularly high frequency of cardiac defects.
- category: Cardiovascular
name: Cutis Marmorata Telangiectatica Congenita
frequency: OCCASIONAL
description: >
A vascular skin anomaly characterized by a persistent reticular
mottling pattern with telangiectasias. Reflects underlying vascular
dysregulation and is more common in Notch pathway-associated subtypes.
phenotype_term:
preferred_term: Cutis marmorata telangiectatica congenita
term:
id: HP:0025107
label: Cutis marmorata telangiectatica congenita
evidence:
- reference: PMID:28160419
reference_title: "Adams-Oliver syndrome review of the literature: Refining the diagnostic phenotype."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Cutis marmorata telangiectasia congenita (CMTC) was found in 19% of the study population and other vascular anomalies were seen in 14%."
explanation: Literature review establishing 19% frequency of CMTC in AOS.
- category: Cardiovascular
name: Pulmonary Arterial Hypertension
frequency: OCCASIONAL
description: >
Pulmonary arterial hypertension can occur in AOS, particularly in
NOTCH1-related cases, and carries significant morbidity and mortality.
phenotype_term:
preferred_term: Pulmonary arterial hypertension
term:
id: HP:0002092
label: Pulmonary arterial hypertension
evidence:
- reference: PMID:38778082
reference_title: "Expanding the phenotypic spectrum of NOTCH1 variants: clinical manifestations in families with congenital heart disease."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "pulmonary hypertension (2/33)"
explanation: NOTCH1 variant carrier cohort documenting pulmonary hypertension in 2 of 33 individuals.
- category: Hepatic
name: Hepatoportal Sclerosis with Portal Hypertension
frequency: OCCASIONAL
description: >
Non-cirrhotic portal hypertension due to hepatoportal sclerosis,
with potential for esophageal varices. Observed particularly in
non-familial AOS cases.
phenotype_term:
preferred_term: Portal hypertension
term:
id: HP:0001409
label: Portal hypertension
evidence:
- reference: PMID:28160419
reference_title: "Adams-Oliver syndrome review of the literature: Refining the diagnostic phenotype."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "A relatively large number of non-familial probands were reported to have hepatoportal sclerosis with portal hypertension and esophageal varices."
explanation: Literature review documenting hepatoportal sclerosis as a notable feature particularly in non-familial AOS cases.
- category: Neurological
name: Central Nervous System Anomalies
frequency: OCCASIONAL
description: >
A wide variety of CNS anomalies including structural defects,
microcephaly, vascular malformations, and migration defects.
Reported in approximately 23% of AOS cases.
phenotype_term:
preferred_term: CNS structural anomaly
term:
id: HP:0002011
label: Morphological central nervous system abnormality
evidence:
- reference: PMID:28160419
reference_title: "Adams-Oliver syndrome review of the literature: Refining the diagnostic phenotype."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "the most commonly associated anomalies included a wide variety of central nervous system (CNS) anomalies and congenital heart defects each seen in 23%. CNS anomalies included structural anomalies, microcephaly, vascular defects, and vascular sequelae. CNS migration defects were common."
explanation: Literature review establishing 23% frequency of CNS anomalies in AOS.
genetic:
- name: ARHGAP31 (AOS1)
gene_term:
preferred_term: ARHGAP31
term:
id: hgnc:29216
label: ARHGAP31
association: CAUSAL
subtype: AOS1
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:21565291
reference_title: "Gain-of-function mutations of ARHGAP31, a Cdc42/Rac1 GTPase regulator, cause syndromic cutis aplasia and limb anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Mutant transcripts are stable and increase ARHGAP31 activity in vitro through a gain-of-function mechanism."
explanation: Heterozygous gain-of-function ARHGAP31 mutations are inherited in an autosomal dominant pattern.
features: >
Gain-of-function mutations produce C-terminally truncated proteins with
constitutive GAP activity toward Cdc42 and Rac1, disrupting cytoskeletal
dynamics and cell migration. Accounts for approximately 3% of AOS cases.
evidence:
- reference: PMID:21565291
reference_title: "Gain-of-function mutations of ARHGAP31, a Cdc42/Rac1 GTPase regulator, cause syndromic cutis aplasia and limb anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Mutant transcripts are stable and increase ARHGAP31 activity in vitro through a gain-of-function mechanism."
explanation: Demonstrates gain-of-function mechanism of ARHGAP31 mutations.
- reference: PMID:29924900
reference_title: "Elucidating the genetic architecture of Adams-Oliver syndrome in a large European cohort."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "ARHGAP31 (3%), EOGT (3%), and RBPJ (2%) representing additional causality in this cohort."
explanation: Large cohort establishing 3% frequency of ARHGAP31 mutations in AOS.
- name: DOCK6 (AOS2)
gene_term:
preferred_term: DOCK6
term:
id: hgnc:19189
label: DOCK6
association: CAUSAL
subtype: AOS2
inheritance:
- name: Autosomal recessive
evidence:
- reference: PMID:21820096
reference_title: "Recessive mutations in DOCK6, encoding the guanidine nucleotide exchange factor DOCK6, lead to abnormal actin cytoskeleton organization and Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "we combined autozygome analysis with exome sequencing to identify a homozygous truncating mutation in dedicator of cytokinesis 6 gene (DOCK6)"
explanation: Homozygous loss-of-function DOCK6 mutations identify autosomal recessive inheritance for AOS2.
features: >
Loss-of-function mutations in DOCK6 reduce GEF activity toward
Cdc42 and Rac1, impairing cytoskeletal regulation and cell migration.
Associated with more severe phenotypes. Accounts for approximately 6% of AOS cases.
evidence:
- reference: PMID:21820096
reference_title: "Recessive mutations in DOCK6, encoding the guanidine nucleotide exchange factor DOCK6, lead to abnormal actin cytoskeleton organization and Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "we combined autozygome analysis with exome sequencing to identify a homozygous truncating mutation in dedicator of cytokinesis 6 gene (DOCK6)"
explanation: Original identification of DOCK6 mutations in AOS.
- reference: PMID:29924900
reference_title: "Elucidating the genetic architecture of Adams-Oliver syndrome in a large European cohort."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "DOCK6 (6%), ARHGAP31 (3%), EOGT (3%), and RBPJ (2%) representing additional causality in this cohort."
explanation: Large cohort establishing 6% frequency of DOCK6 mutations in AOS.
- reference: CGGV:assertion_ea64d74c-583d-4ed1-af91-6a7c6f80a1d3-2022-06-28T160000.000Z
reference_title: "DOCK6 / Adams-Oliver syndrome (Definitive)"
supports: SUPPORT
evidence_source: OTHER
snippet: "DOCK6 | HGNC:19189 | Adams-Oliver syndrome | MONDO:0007034 | AR | Definitive"
explanation: ClinGen classifies the DOCK6-Adams-Oliver syndrome gene-disease relationship as definitive with autosomal recessive inheritance.
- name: RBPJ (AOS3)
gene_term:
preferred_term: RBPJ
term:
id: hgnc:5724
label: RBPJ
association: CAUSAL
subtype: AOS3
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:22883147
reference_title: "RBPJ mutations identified in two families affected by Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Functional assays confirmed impaired DNA binding of mutated RBPJ, placing it among other notch-pathway proteins altered in human genetic syndromes."
explanation: Heterozygous dominant-negative RBPJ mutations are transmitted in autosomal dominant fashion in AOS3 families.
features: >
Dominant-negative mutations in RBPJ compromise DNA binding but retain
cofactor binding, sequestering Notch pathway cofactors from target
gene promoters. Accounts for approximately 2% of AOS cases.
evidence:
- reference: PMID:22883147
reference_title: "RBPJ mutations identified in two families affected by Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Functional assays confirmed impaired DNA binding of mutated RBPJ, placing it among other notch-pathway proteins altered in human genetic syndromes."
explanation: Demonstrates functional impact of RBPJ mutations on DNA binding.
- reference: PMID:41055965
reference_title: "Defective Notch1 signaling in endothelial cells drives pathogenesis in a mouse model of Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "AOS-associated RBPJ missense variants compromise DNA binding but not cofactor binding. These findings suggest that AOS-associated RBPJ variants do not function as loss-of-function alleles but instead act as dominant-negative proteins that sequester cofactors from DNA."
explanation: Demonstrates dominant-negative mechanism of RBPJ mutations - they retain cofactor binding while losing DNA binding, titrating cofactors away from DNA.
- name: EOGT (AOS4)
gene_term:
preferred_term: EOGT
term:
id: hgnc:28526
label: EOGT
association: CAUSAL
subtype: AOS4
inheritance:
- name: Autosomal recessive
evidence:
- reference: PMID:23522784
reference_title: "Mutations in EOGT confirm the genetic heterogeneity of autosomal-recessive Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "EOGT encodes EGF-domain-specific O-linked N-acetylglucosamine (O-GlcNAc) transferase, which is involved in the O-GlcNAcylation (attachment of O-GlcNAc to serine and threonine residues) of a subset of extracellular EGF-domain-containing proteins."
explanation: Biallelic EOGT mutations confer autosomal recessive AOS4, as established in the title and original report.
features: >
Loss-of-function mutations in EOGT impair O-GlcNAcylation of Notch
receptor EGF repeats, disrupting Notch signaling modulation.
Accounts for approximately 3% of AOS cases.
evidence:
- reference: PMID:23522784
reference_title: "Mutations in EOGT confirm the genetic heterogeneity of autosomal-recessive Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "EOGT encodes EGF-domain-specific O-linked N-acetylglucosamine (O-GlcNAc) transferase, which is involved in the O-GlcNAcylation (attachment of O-GlcNAc to serine and threonine residues) of a subset of extracellular EGF-domain-containing proteins."
explanation: Identifies EOGT function and its connection to Notch signaling.
- reference: PMID:29924900
reference_title: "Elucidating the genetic architecture of Adams-Oliver syndrome in a large European cohort."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "ARHGAP31 (3%), EOGT (3%), and RBPJ (2%) representing additional causality in this cohort."
explanation: Large cohort establishing 3% frequency of EOGT mutations in AOS.
- name: NOTCH1 (AOS5)
gene_term:
preferred_term: NOTCH1
term:
id: hgnc:7881
label: NOTCH1
association: CAUSAL
subtype: AOS5
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:25132448
reference_title: "Mutations in NOTCH1 cause Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "we report five heterozygous NOTCH1 variants in unrelated individuals with Adams-Oliver syndrome (AOS), a rare disease with major features of aplasia cutis of the scalp and terminal transverse limb defects."
explanation: Heterozygous NOTCH1 variants establish autosomal dominant inheritance for AOS5.
features: >
Loss-of-function mutations causing NOTCH1 haploinsufficiency.
This is the most common genetic subtype, underlying 10% of AOS cases.
Strong genotype-phenotype correlation with cardiac anomalies (47%
of NOTCH1-positive cases). Impairs Notch signaling in endothelial
cells, cardiac development, and skeletal morphogenesis.
evidence:
- reference: PMID:25132448
reference_title: "Mutations in NOTCH1 cause Adams-Oliver syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "we report five heterozygous NOTCH1 variants in unrelated individuals with Adams-Oliver syndrome (AOS), a rare disease with major features of aplasia cutis of the scalp and terminal transverse limb defects."
explanation: Original identification of NOTCH1 mutations in AOS.
- reference: PMID:25963545
reference_title: "Haploinsufficiency of the NOTCH1 Receptor as a Cause of Adams-Oliver Syndrome With Variable Cardiac Anomalies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "NOTCH1 transcript levels were significantly reduced by comparison to an unaffected control individual, demonstrating approximately 50% expression in all samples tested"
explanation: Demonstrates NOTCH1 haploinsufficiency as the molecular mechanism.
- reference: PMID:29924900
reference_title: "Elucidating the genetic architecture of Adams-Oliver syndrome in a large European cohort."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "NOTCH1 is the major contributor, underlying 10% of AOS/ACC/TTLD cases"
explanation: Large cohort confirming NOTCH1 as the most common genetic cause of AOS.
- name: DLL4 (AOS6)
gene_term:
preferred_term: DLL4
term:
id: hgnc:2910
label: DLL4
association: CAUSAL
subtype: AOS6
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:26299364
reference_title: "Heterozygous Loss-of-Function Mutations in DLL4 Cause Adams-Oliver Syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Our findings demonstrate that DLL4 mutations are an additional cause of autosomal-dominant AOS or isolated ACC and provide further evidence for a key role of NOTCH signaling in the etiology of this disorder."
explanation: Heterozygous DLL4 loss-of-function variants establish autosomal dominant inheritance for AOS6.
features: >
Loss-of-function mutations in DLL4, a key Notch ligand for
angiogenesis and vascular patterning. Accounts for approximately 6%
of AOS cases. Associated with cardiac outflow tract defects through
disruption of second heart field progenitor biology.
evidence:
- reference: PMID:26299364
reference_title: "Heterozygous Loss-of-Function Mutations in DLL4 Cause Adams-Oliver Syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Our findings demonstrate that DLL4 mutations are an additional cause of autosomal-dominant AOS or isolated ACC and provide further evidence for a key role of NOTCH signaling in the etiology of this disorder."
explanation: Establishes DLL4 as a cause of autosomal dominant AOS.
- reference: PMID:29924900
reference_title: "Elucidating the genetic architecture of Adams-Oliver syndrome in a large European cohort."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "DLL4 (6%), DOCK6 (6%), ARHGAP31 (3%), EOGT (3%), and RBPJ (2%) representing additional causality in this cohort."
explanation: Large cohort establishing 6% frequency of DLL4 mutations in AOS.
- reference: PMID:33899511
reference_title: "Murine Model of Cardiac Defects Observed in Adams-Oliver Syndrome Driven by Delta-Like Ligand-4 Haploinsufficiency."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "Similar to the clinical syndrome, 32% of SHF-specific Dll4 heterozygotes demonstrate foreshortened and misaligned OFT, resulting in a double outlet right ventricle."
explanation: Mouse model providing molecular mechanism for cardiac defects in DLL4-related AOS.
treatments:
- name: Wound Care for Aplasia Cutis
description: >
Conservative wound management of scalp defects with moist wound dressings
and infection prevention. Most small to moderate aplasia cutis lesions
heal spontaneously with conservative care.
treatment_term:
preferred_term: wound care management
term:
id: MAXO:0000950
label: supportive care
- name: Surgical Reconstruction
description: >
Surgical intervention for large scalp defects, exposed dura, or significant
limb deficiencies. May include skin grafting, tissue expansion, or
prosthetic fitting for limb defects.
treatment_term:
preferred_term: surgical procedure
term:
id: MAXO:0000004
label: surgical procedure
- name: Genetic Counseling
description: >
Genetic counseling for families with AOS to discuss inheritance patterns,
recurrence risks, and available genetic testing options. Important given
the genetic heterogeneity (6 known genes) and variable inheritance patterns
(autosomal dominant and recessive forms).
treatment_term:
preferred_term: genetic counseling
term:
id: MAXO:0000079
label: genetic counseling
prevalence:
- population: General population
percentage: Unknown (very rare)
notes: >
AOS is a very rare disorder with unknown precise prevalence.
Molecular diagnostic screening achieves a diagnostic yield of
approximately 36% in familial cases and 30% overall, suggesting
additional undiscovered genetic causes.
evidence:
- reference: PMID:29924900
reference_title: "Elucidating the genetic architecture of Adams-Oliver syndrome in a large European cohort."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Molecular diagnostic screening of 194 AOS/ACC/TTLD probands/families was conducted using next-generation and/or capillary sequencing analyses. In total, we identified 63 (likely) pathogenic mutations, comprising 56 distinct and 22 novel mutations, providing a molecular diagnosis in 30% of patients."
explanation: Large cohort study providing molecular diagnostic yield data for AOS.
datasets:
This report is retrieval-only and is generated directly from Asta results.
search_papers_by_relevance with snippet_search.