chr6-121447073-C-A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1PM2PM5PP2PP3_StrongPP5

The NM_000165.5(GJA1):c.226C>A(p.Arg76Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R76H) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 32)

Consequence

GJA1
NM_000165.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4U:1

Conservation

PhyloP100: 7.91

Publications

14 publications found

Variant links:

Genes affected

GJA1 (HGNC:4274): (gap junction protein alpha 1) 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]

GJA1 Gene-Disease associations (from GenCC):

hypoplastic left heart syndrome 1
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
oculodentodigital dysplasia
Inheritance: AD, SD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics
autosomal dominant palmoplantar keratoderma and congenital alopecia
Inheritance: AD Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Orphanet, Ambry Genetics, Genomics England PanelApp, G2P
erythrokeratodermia variabilis et progressiva 3
Inheritance: AD Classification: STRONG, MODERATE, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P
oculodentodigital dysplasia, autosomal recessive
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
craniometaphyseal dysplasia
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
erythrokeratodermia variabilis
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
syndactyly type 3
Inheritance: AD, Unknown Classification: SUPPORTIVE, LIMITED Submitted by: Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
Hallermann-Streiff syndrome
Inheritance: AR Classification: LIMITED Submitted by: G2P
craniometaphyseal dysplasia, autosomal recessive
Inheritance: Unknown, AR Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
nonsyndromic genetic hearing loss
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

GJA1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000165.5

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr6-121447074-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 16996.Status of the report is no_assertion_criteria_provided, 0 stars.

PP2

Missense variant in the GJA1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 41 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 1.2784 (below the threshold of 3.09). Trascript score misZ: 3.3775 (above the threshold of 3.09). GenCC associations: The gene is linked to craniometaphyseal dysplasia, autosomal recessive, erythrokeratodermia variabilis et progressiva 3, oculodentodigital dysplasia, autosomal dominant palmoplantar keratoderma and congenital alopecia, hypoplastic left heart syndrome 1, craniometaphyseal dysplasia, syndactyly type 3, oculodentodigital dysplasia, autosomal recessive, nonsyndromic genetic hearing loss, Hallermann-Streiff syndrome, erythrokeratodermia variabilis.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.995

PP5

Variant 6-121447073-C-A is Pathogenic according to our data. Variant chr6-121447073-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 16997.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJA1	NM_000165.5 link	c.226C>A	p.Arg76Ser	missense_variant	Exon 2 of 2	ENST00000282561.4	NP_000156.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
GJA1	ENST00000282561.4 link	c.226C>A	p.Arg76Ser	missense_variant	Exon 2 of 2	1	NM_000165.5	ENSP00000282561.3
GJA1	ENST00000647564.1 link	c.226C>A	p.Arg76Ser	missense_variant	Exon 2 of 2			ENSP00000497565.1
GJA1	ENST00000649003.1 link	c.226C>A	p.Arg76Ser	missense_variant	Exon 2 of 2			ENSP00000497283.1
GJA1	ENST00000650427.1 link	c.226C>A	p.Arg76Ser	missense_variant	Exon 2 of 2			ENSP00000497367.1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Cov.:

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Oculodentodigital dysplasia

Pathogenic:3

May 12, 2014

Genetic Services Laboratory, University of Chicago

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 01, 2003

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Dec 07, 2021

Greenwood Genetic Center Diagnostic Laboratories, Greenwood Genetic Center

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

PM2, PM5, PS5_Supporting, PP3 -

not provided

Pathogenic:1

Aug 08, 2025

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Reported previously segregating in a family with oculodentodigital dysplasia however detailed clinical or segregation information was not specified (PMID: 10331943; 12457340); Published functional studies suggest that R76S results in reduced gap activity in vitro; however additional studies are needed to validate the functional effect of this variant in vivo (PMID: 34630166); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 32318302, 30626485, Katturajan 2023[computational], 37395717, 12457340, 34630166) -

Oculodentodigital dysplasia, autosomal recessive

Uncertain:1

Apr 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 76 of the GJA1 protein (p.Arg76Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with oculodentodigital dysplasia (PMID: 12457340). ClinVar contains an entry for this variant (Variation ID: 16997). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GJA1 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects GJA1 function (PMID: 34630166). This variant disrupts the p.Arg76 amino acid residue in GJA1. Other variant(s) that disrupt this residue have been observed in individuals with GJA1-related conditions (PMID: 12457340, 24115525), which suggests that this may be a clinically significant amino acid residue. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.57

BayesDel_noAF

Pathogenic

0.59

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.98

D;D;D;D;D

Eigen

Pathogenic

0.92

Eigen_PC

Pathogenic

0.87

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.87

.;.;.;.;D

M_CAP

Pathogenic

0.81

MetaRNN

Pathogenic

0.99

D;D;D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.2

M;M;M;M;M

PhyloP100

7.9

PrimateAI

Pathogenic

0.93

PROVEAN

Pathogenic

-5.4

.;.;D;.;.

REVEL

Pathogenic

0.98

Sift

Pathogenic

0.0

.;.;D;.;.

Sift4G

Uncertain

0.0020

.;.;D;.;.

Polyphen

1.0

D;D;D;D;D

Vest4

0.94

MutPred

0.98

Gain of catalytic residue at S73 (P = 0.1025);Gain of catalytic residue at S73 (P = 0.1025);Gain of catalytic residue at S73 (P = 0.1025);Gain of catalytic residue at S73 (P = 0.1025);Gain of catalytic residue at S73 (P = 0.1025);

MVP

0.99

MPC

1.4

ClinPred

1.0

GERP RS

5.5

Varity_R

0.94

gMVP

1.0

Mutation Taster

=6/94

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over