GENE REFERENCE / HGNC:4274

GJA1

gap junction protein alpha 1

protein-coding gene6q22.31Gene information

What does this gene do?

The GJA1 gene provides instructions for making a protein called gap junction alpha-1 protein. Because this protein is one of a large family of connexin proteins, it is commonly called connexin 43. Connexins play a role in cell-to-cell communication by forming channels, or gap junctions, on the surface of cells. Gap junctions allow for the transport of nutrients, charged particles (ions), and other small molecules that carry necessary communication signals between cells. Connexin 43 is important for the normal development and function of cells in many different tissues of the body, including the eyes, skin, bone, ears, and brain. Connexin 43 is also thought to play a role in coordinating muscle cell contractions, which helps the heart pump blood effectively.

Source: MedlinePlus, National Library of Medicine. Source publication: 2025-09-26. Source review: 2025-03.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
congenital heart diseaseMONDO:0005453 · Evaluated 2024-06-04	Not specified (UD)	LimitedCongenital Heart Disease Gene Curation Expert Panel
nonsyndromic genetic hearing lossMONDO:0019497 · Evaluated 2022-03-16	Autosomal dominant	DisputedHearing Loss Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 408
Submissions for variants in or overlapping this gene: 741
Submissions explicitly reporting this gene: 706
Alleles reported pathogenic / likely pathogenic: 62
VariationIDs with uncertain significance: 215
VariationIDs with conflicting classifications: 22

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about GJA1?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 62 alleles in GJA1 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in GJA1.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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