GJB1

Chr X

gap junction protein beta 1

Also known as: CMTX, CMTX1, CX32

NCBI Gene: 2705ENSG00000169562UniProt: P08034

This gene encodes a member of the gap junction protein family. The gap junction proteins are membrane-spanning proteins that assemble to form gap junction channels that facilitate the transfer of ions and small molecules between cells. According to sequence similarities at the nucleotide and amino acid levels, the gap junction proteins are divided into two categories, alpha and beta. Mutations in this gene cause X-linked Charcot-Marie-Tooth disease, an inherited peripheral neuropathy. Alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Oct 2008]

GeneReviewsResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtCharcot-Marie-Tooth disease, X-linked dominant, 1
UniProtDejerine-Sottas syndrome

Clinical highlights

Gene-disease validity (ClinGen)
Charcot-Marie-Tooth disease X-linked dominant 1 · XLDefinitivesufficient evidence for diagnostic panels
Interpreting a novel variant
This gene is strongly intolerant of loss-of-function variation in the population, so LoF variants warrant close attention. No curated mechanism annotation is available — see the mechanism card for the computational prediction and its caveats.Based on population constraint only.
0
Active trials
35
Pubs (1 yr)
—
P/LP submissions
—
P/LP missense
0.49
LOEUF
GOF
Mechanism· predicted
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GeneReview available — GJB1
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Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Moderate LoF intolerance
LoF Constraint?
0.49LOEUF
pLI 0.846
Z-score 2.30
OE 0.00 (0.00–0.49)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint?
2.03Z-score
OE missense 0.50 (0.41–0.62)
66 obs / 131.4 exp
Mild constraint

Moderately missense-constrained (top ~2.5%)

Observed / Expected Ratios?
LoF OE?0.00 (0.00–0.49)
0≤0.351.4
Missense OE?0.50 (0.41–0.62)
0≤0.61.4
Synonymous OE?0.93
0≤1.21.6
LoF obs/exp: 0 / 6.2Missense obs/exp: 66 / 131.4Syn Z: 0.41

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

GJB1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools

Franklin by Genoox
AI-powered variant curation and clinical analysis
DECIPHER
Genomic variants and phenotypes in rare disease patients