GJA1

protein-coding

gap junction protein alpha 1, the group of Gap junction proteins

Gene summary

This gene is a member of the connexin gene family. The encoded protein is a component of gap junctions, which are composed of arrays of intercellular channels that provide a route for the diffusion of low molecular weight materials from cell to cell. The encoded protein is the major protein of gap junctions in the heart that are thought to have a crucial role in the synchronized contraction of the heart and in embryonic development. A related intronless pseudogene has been mapped to chromosome 5. Mutations in this gene have been associated with oculodentodigital dysplasia, autosomal recessive craniometaphyseal dysplasia and heart malformations. [provided by RefSeq, May 2014]

Previous symbols:
  • ODDD
  • GJAL

MANE transcript

NM_000165.5

Inheritance

AD, AR, SD

ClinVar variants

P:65U:176B:89

Top phenotype

Oculodentodigital dysplasia; Hypoplastic left heart syndrome 1; Atrioventricular septal defect 3

gnomAD constraint

pLI —, LoF o/e 0.27

Max pathogenic AF

—

Genomic locus

chr6:121,435,595-121,449,727

External References & Databases

Transcript & Mutation Effects

hg38 • Region Span ~14.1 kb
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GenCC Phenotypes & Disease Associations

Curated gene-disease validity assertions and inheritance patterns

autosomal dominant palmoplantar keratoderma and congenital alopeciaLIMITED

Inheritance Pattern: AD

Disease ID:MONDO:0007083

Submitter: Ambry Genetics

craniometaphyseal dysplasia, autosomal recessiveLIMITED

Inheritance Pattern: Unknown

Disease ID:MONDO:0009035

Submitter: Labcorp Genetics (formerly Invitae)

erythrokeratodermia variabilisSUPPORTIVE

Inheritance Pattern: AD

Disease ID:MONDO:0017851

Submitter: Orphanet

erythrokeratodermia variabilis et progressiva 3STRONG

Inheritance Pattern: AD

Disease ID:MONDO:0033013

Submitter: Genomics England PanelApp

oculodentodigital dysplasiaSUPPORTIVE

Inheritance Pattern: AD

Disease ID:MONDO:0008111

Submitter: Orphanet

autosomal dominant palmoplantar keratoderma and congenital alopeciaSTRONG

Inheritance Pattern: AD

Disease ID:MONDO:0007083

Submitter: Genomics England PanelApp

syndactyly type 3SUPPORTIVE

Inheritance Pattern: AD

Disease ID:MONDO:0008514

Submitter: Orphanet

oculodentodigital dysplasiaDEFINITIVE

Inheritance Pattern: AR

Disease ID:MONDO:0008111

Submitter: G2P

autosomal dominant palmoplantar keratoderma and congenital alopeciaSUPPORTIVE

Inheritance Pattern: AD

Disease ID:MONDO:0007083

Submitter: Orphanet

craniometaphyseal dysplasiaSUPPORTIVE

Inheritance Pattern: AD

Disease ID:MONDO:0015465

Submitter: Orphanet

oculodentodigital dysplasia, autosomal recessiveMODERATE

Inheritance Pattern: AR

Disease ID:MONDO:0009768

Submitter: Ambry Genetics

oculodentodigital dysplasiaDEFINITIVE

Inheritance Pattern: AD

Disease ID:MONDO:0008111

Submitter: Ambry Genetics

oculodentodigital dysplasiaDEFINITIVE

Inheritance Pattern: SD

Disease ID:MONDO:0008111

Submitter: Ambry Genetics

congenital heart diseaseLIMITED

Inheritance Pattern: Unknown

Disease ID:MONDO:0005453

Submitter: ClinGen

*GJA1* was first reported in relation to congenital heart disease in 1995 (Britz-Cunningham et al., PMID: 7715640). This gene-disease relationship in the literature reports both autosomal dominant and recessive cases and showed varying mechanisms of pathogenicity, so the mode of inheritance is currently undetermined. Three unique variants (missense) reported in three individuals with CHD (1 homozygous, 2 heterozygous) are included in this curation (PMID: 15978203, 19615768). There are more variants reported in other publications, however they were not included due to either unclear phenotype, high minor allele frequency (>0.00001) on gnomAD v.4, or unclear mode of inheritance with multiple variants reported in the proband (PMID: 7715640, 11470490, 19615768, 28991257, 32368696, 31564432, 31019026, 34670123). This gene-disease relationship is also supported by expression data in both mouse and human cardiac tissues (PMIDs: 12064615, 12881038). One mouse study showed that both heterozygous and homozygous *GJA1* knock-in mice were long term viable with no heart defects (PMID: 22135478). Conversely, there are also several mouse studies showing heart defects in mice mutants, however none were scored due to inconsistent mechanisms of pathogenicity (PMIDs: 7892609, 9640330, 9486664, 9118799). In summary, there is limited evidence supporting the relationship between *GJA1* and congenital heart disease. Although more evidence is needed to support a causal role, the contradictory evidence does not significantly outweigh the evidence that supports the gene-disease relationship either. This classification was approved by the ClinGen Congenital Heart Disease GCEP on the meeting date June 4th, 2024 (SOP Version 10).

syndactyly type 3LIMITED

Inheritance Pattern: AD

Disease ID:MONDO:0008514

Submitter: Ambry Genetics

oculodentodigital dysplasiaSTRONG

Inheritance Pattern: AD

Disease ID:MONDO:0008111

Submitter: Labcorp Genetics (formerly Invitae)

oculodentodigital dysplasia, autosomal recessiveSTRONG

Inheritance Pattern: AR

Disease ID:MONDO:0009768

Submitter: Labcorp Genetics (formerly Invitae)

nonsyndromic genetic hearing lossNO_KNOWN

Inheritance Pattern: AD

Disease ID:MONDO:0019497

Submitter: ClinGen

GJA1 was first reported in relation to autosomal dominant nonsyndromic hearing loss (AD NSHL) in 2001 (Liu et al., PMID: 11741837). At least 1 missense, 1 splicing, and 1 nonsense variant have been reported in humans. Two variants reported (Liu et al. 2001, PMID: 11741837) were subsequently shown to be located in a pseudogene (Pazenkas et al. 2003, PMID: 12457340). Three additional variants have no evidence of pathogenicity (PMIDs: 17259707, 23141803, ​​25724631). Of note, this gene has also been implicated in autosomal dominant atrioventricular septal defect 3, autosomal recessive craniometaphyseal dysplasia, autosomal dominant erythrokeratodermia variabilis et progressiva 3, autosomal recessive hypoplastic left heart syndrome 1, autosomal dominant oculodentodigital dysplasia, autosomal recessive oculodentodigital dysplasia, autosomal dominant palmoplantar keratoderma with congenital alopecia, and autosomal dominant syndactyly, type III. These will be assessed separately. In summary, the evidence supporting the relationship between GJA1 and AD NSHL has been disputed and no valid evidence remains to support the claim. More evidence is needed to either support or entirely refute the role GJA1 plays in this disease. This gene-disease pair was originally evaluated by the Hearing Loss GCEP on 1/16/2018. It was reevaluated on 3/16/2022. Although additional publications were identified (PMIDs: 26185573, 25724631, 35023121), they did not contain valid scorable evidence. Therefore, as a result of this reevaluation, the classification did not change.

craniometaphyseal dysplasia, autosomal recessiveLIMITED

Inheritance Pattern: AR

Disease ID:MONDO:0009035

Submitter: Ambry Genetics

erythrokeratodermia variabilis et progressiva 3LIMITED

Inheritance Pattern: AD

Disease ID:MONDO:0033013

Submitter: Ambry Genetics

erythrokeratodermia variabilis et progressiva 3MODERATE

Inheritance Pattern: AD

Disease ID:MONDO:0033013

Submitter: G2P

autosomal dominant palmoplantar keratoderma and congenital alopeciaLIMITED

Inheritance Pattern: AD

Disease ID:MONDO:0007083

Submitter: G2P

syndactyly type 3LIMITED

Inheritance Pattern: Unknown

Disease ID:MONDO:0008514

Submitter: Labcorp Genetics (formerly Invitae)

erythrokeratodermia variabilis et progressiva 3STRONG

Inheritance Pattern: AD

Disease ID:MONDO:0033013

Submitter: Labcorp Genetics (formerly Invitae)

oculodentodigital dysplasiaDEFINITIVE

Inheritance Pattern: AD

Disease ID:MONDO:0008111

Submitter: G2P

Clinical Genomic Database (CGD)

Oculodentodigital dysplasia; Hypoplastic left heart syndrome 1; Atrioventricular septal defect 3AD/AR

Manifestation: Cardiovascular; Craniofacial; Dental; Dermatologic; Endocrine; Musculoskeletal; Neurologic; Ophthalmologic

Intervention: Cardiovascular

Rationale: Individuals with congenital heart anomalies may benefit from early diagnosis and intervention; Individuals with cardiac arrhythmias have been reported, and surveillance (eg, with EKG) may allow early detection and treatment

Refs: 2157843; 7815444; 11470490; 12457340; 15108203; 14974090; 14729836; 14981729; 15551259; 15637728; 16709485; 16816024; 17256797; 18412120; 19338053; 21670345; 22179534; 22214631; 23951358; 25168385; 25398053Source: CGD (NHGRI)

ClinVar Associated Diseases & Phenotypes

Reported disease conditions connected to GJA1 variants in ClinVar

26 Conditions Cataloged
Oculodentodigital dysplasia, autosomal recessiveTotal: 244
not providedTotal: 90
Oculodentodigital dysplasiaTotal: 63
Inborn genetic diseasesTotal: 33
not specifiedTotal: 33
Syndactyly type 3Total: 28
Hypoplastic left heart syndrome 1Total: 22
GJA1-related disorderTotal: 21

ClinVar Variants & Pathogenicity by Type

Statistics based on transcript NM_000165.5. Only rare variants are included.

We include only reliable ClinVar variants with their consequences to MANE Select, MANE Plus Clinical transcripts, or transcripts with TSL equal to 1. Click a count to filter the variants table below.

Slight differences between displayed counts and ClinVar may occur due to a different transcript/consequence chosen by our variant effect predictor, or because we classify Benign/Likely benign as Likely benign and Pathogenic/Likely pathogenic as Likely pathogenic.

EffectPLPVUSLBBSum
synonymous
4
clinvar
80
clinvar
1
clinvar
85
missense
26
clinvar
31
clinvar
162
clinvar
8
clinvar
227
nonsense
2
clinvar
2
clinvar
2
clinvar
6
start loss
0
frameshift
2
clinvar
2
clinvar
8
clinvar
12
splice donor/acceptor (+/-2bp)
0
Total3035176881330

Highest pathogenic variant AF is 0.000010533412

Loading ClinVar variants...

Transcript Catalog

Annotated transcript isoforms across RefSeq and Ensembl databases

Showing 4 of 14 transcripts
Transcript IDSourceProtein IDCoding ExonsMANE Status
NM_000165.5RefSeqNP_000156.11MANE Select
ENST00000282561.4EnsemblENSP00000282561.31MANE Select
ENST00000647564.1EnsemblENSP00000497565.11Standard
ENST00000647564.2EnsemblENSP00000497565.11Standard

Model Organisms & Knockout Phenotypes

Observed phenotypic effects in mouse and zebrafish models

Gene / ModelOrganismObserved Phenotype
cx43Danio rerio

Structure: nucleate erythrocyte

Quality: decreased amount

abnormal

Gene Ontology (GO) Annotations & Pathways

Biological processes, molecular functions, cellular components and pathways

Pathways ConsensusPathDB

  • Arrhythmogenic right ventricular cardiomyopathy (ARVC) - Homo sapiens (human)
  • Gap junction - Homo sapiens (human)
  • Antiarrhythmic Pathway, Pharmacodynamics
  • TarBasePathway
  • miR-targeted genes in epithelium - TarBase

Biological Process

  • muscle contraction
  • signal transduction
  • cell-cell signaling
  • heart development
  • cell communication by electrical coupling

Molecular Function

  • gap junction channel activity
  • protein binding
  • ion transmembrane transporter activity
  • gap junction hemi-channel activity
  • gap junction channel activity involved in cardiac conduction electrical coupling

Cellular Component

  • Golgi membrane
  • nucleoplasm
  • mitochondrion
  • endoplasmic reticulum membrane
  • Golgi apparatus

gnomAD Constraint

Source: gnomAD

Gene type
protein_coding
Transcript type
protein_coding
Transcript
ENST00000282561
Coding exons
1
Length
14036
Individuals with no LoFs
125735
Homozygous LoFs
0
Heterozygous LoFs
13
Defined
125748
p
0.0000517
Z-ScoreObservedExpectedObserved/ExpectedMutation RateTotal Possible
Missense1.281502010.7460.00001182506
Missense (PolyPhen)1762.9190.27019862
Synonymous-2.6511180.71.380.00000486760
Loss of Function2.58414.70.2730.00000117151

Population LoF Frequency

PopulationCAFp-valueStatus
African00.0absent
Latino/Admixed American0.000170.00017rare
Ashkenazi Jewish00.0absent
East Asian0.0000540.000054rare
Finnish00.0absent
European (Non-Finnish)0.0000440.000044rare
South Asian0.0000330.000033rare
Other00.0absent

dbNSFP Gene Annotations

Source: dbNSFP

Function
FUNCTION: Gap junction protein that acts as a regulator of bladder capacity. A gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell. May play a critical role in the physiology of hearing by participating in the recycling of potassium to the cochlear endolymph. Negative regulator of bladder functional capacity: acts by enhancing intercellular electrical and chemical transmission, thus sensitizing bladder muscles to cholinergic neural stimuli and causing them to contract (By similarity). May play a role in cell growth inhibition through the regulation of NOV expression and localization. Plays an essential role in gap junction communication in the ventricles (By similarity). {ECO:0000250|UniProtKB:P08050, ECO:0000250|UniProtKB:P23242}.;
Disease
DISEASE: Oculodentodigital dysplasia (ODDD) [MIM:164200]: A disease characterized by a typical facial appearance and variable involvement of the eyes, dentition, and fingers. Characteristic facial features include a narrow, pinched nose with hypoplastic alae nasi, prominent columella and thin anteverted nares together with a narrow nasal bridge, and prominent epicanthic folds giving the impression of hypertelorism. The teeth are usually small and carious. Typical eye findings include microphthalmia and microcornea. The characteristic digital malformation is complete syndactyly of the fourth and fifth fingers (syndactyly type III) but the third finger may be involved and associated camptodactyly is a common finding. Cardiac abnormalities are observed in rare instances. {ECO:0000269|PubMed:12457340, ECO:0000269|PubMed:14729836, ECO:0000269|PubMed:15108203, ECO:0000269|PubMed:15637728, ECO:0000269|PubMed:16219735, ECO:0000269|PubMed:16222672, ECO:0000269|PubMed:16378922, ECO:0000269|PubMed:16709485, ECO:0000269|PubMed:16813608, ECO:0000269|PubMed:16816024, ECO:0000269|PubMed:17509830, ECO:0000269|PubMed:18161618, ECO:0000269|PubMed:19338053, ECO:0000269|PubMed:21670345, ECO:0000269|PubMed:23550541, ECO:0000269|PubMed:24508941, ECO:0000269|PubMed:28258662}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Oculodentodigital dysplasia, autosomal recessive (ODDD- AR) [MIM:257850]: A disease characterized by a typical facial appearance and variable involvement of the eyes, dentition, and fingers. Characteristic facial features include a narrow, pinched nose with hypoplastic alae nasi, prominent columella and thin anteverted nares together with a narrow nasal bridge, and prominent epicanthic folds giving the impression of hypertelorism. The teeth are usually small and carious. Typical eye findings include microphthalmia and microcornea. The characteristic digital malformation is complete syndactyly of the fourth and fifth fingers (syndactyly type III) but the third finger may be involved and associated camptodactyly is a common finding. Cardiac abnormalities are observed in rare instances. {ECO:0000269|PubMed:16816024}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Syndactyly 3 (SDTY3) [MIM:186100]: A form of syndactyly, a congenital anomaly of the hand or foot marked by persistence of the webbing between adjacent digits that are more or less completely attached. In SDTY3, there is usually complete and bilateral syndactyly between the fourth and fifth fingers. Usually it is soft tissue syndactyly but occasionally the distal phalanges are fused. The fifth finger is short with absent or rudimentary middle phalanx. The feet are not affected. {ECO:0000269|PubMed:14729836}. Note=The disease may be caused by mutations affecting the gene represented in this entry.; DISEASE: Hypoplastic left heart syndrome 1 (HLHS1) [MIM:241550]: A syndrome due to defective development of the aorta proximal to the entrance of the ductus arteriosus, and hypoplasia of the left ventricle and mitral valve. As a result of the abnormal circulation, the ductus arteriosus and foramen ovale are patent and the right atrium, right ventricle, and pulmonary artery are enlarged. {ECO:0000269|PubMed:11470490}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Hallermann-Streiff syndrome (HSS) [MIM:234100]: A disorder characterized by a typical skull shape (brachycephaly with frontal bossing), hypotrichosis, microphthalmia, cataracts, beaked nose, micrognathia, skin atrophy, dental anomalies and proportionate short stature. Mental retardation is present in a minority of cases. {ECO:0000269|PubMed:14974090}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Atrioventricular septal defect 3 (AVSD3) [MIM:600309]: A congenital heart malformation characterized by a common atrioventricular junction coexisting with deficient atrioventricular septation. The complete form involves underdevelopment of the lower part of the atrial septum and the upper part of the ventricular septum; the valve itself is also shared. A less severe form, known as ostium primum atrial septal defect, is characterized by separate atrioventricular valvar orifices despite a common junction. {ECO:0000269|PubMed:11470490}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Craniometaphyseal dysplasia, autosomal recessive (CMDR) [MIM:218400]: An osteochondrodysplasia characterized by hyperostosis and sclerosis of the craniofacial bones associated with abnormal modeling of the metaphyses. Sclerosis of the skull may lead to asymmetry of the mandible, as well as to cranial nerve compression, that may finally result in hearing loss and facial palsy. {ECO:0000269|PubMed:23951358}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Erythrokeratodermia variabilis et progressiva 3 (EKVP3) [MIM:617525]: A form of erythrokeratodermia variabilis et progressiva, a genodermatosis characterized by the coexistence of two independent skin lesions: transient erythema and hyperkeratosis that is usually localized but occasionally occurs in its generalized form. Clinical presentation varies significantly within a family and from one family to another. Palmoplantar keratoderma is present in around 50% of cases. {ECO:0000269|PubMed:25398053}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Palmoplantar keratoderma and congenital alopecia 1 (PPKCA1) [MIM:104100]: A rare autosomal dominant disorder characterized by severe hyperkeratosis of the palms and soles, and congenital hypotrichosis or alopecia. Dystrophic nail changes occur in some patients. {ECO:0000269|PubMed:25168385}. Note=The disease is caused by mutations affecting the gene represented in this entry.;

Recessive Scores

pRec
0.365

Intolerance Scores

LoFtool
0.108
RVIS EVS
-0.27
RVIS percentile EVS
34.32

Essentials

Essential (CRISPR)
N
Essential (CRISPR2)
N
Essential (gene trap)
N
Indispensability pred.
E
Indispensability score
0.583

Gene Damage Prediction

AllRecessiveDominant
MendelianMediumMediumMedium
Primary ImmunodeficiencyMediumMediumMedium
CancerMediumMediumMedium
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