Skip to content
Use your HSA or FSA funds

Gene

GJB1

gap junction protein beta 1

Summary

Cytogenetic location
Xq13.1
Coordinates
Chromosome X: 71,223,224–71,225,516 (GRCh38)
Exons
2 exons across 2.3 kb
Protein
283 amino acids
Also known as
CX32
Previous symbols
CMTX1, CMTX
MANE Select transcript
ENST00000361726.7NM_000166.6
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated report relevant to this gene

    • Charcot-Marie-Tooth Disease

      • One of 62 genes linked to it

        A group of inherited peripheral neuropathies causing progressive weakness and wasting of the distal muscles and loss of sensation, mainly in the feet and hands.

        • ClinGen rates the link definitive
        • 4 GenCC submitters rate it definitive or strong
        What knowing changes

        Genetic counseling, subtype-specific monitoring, physical therapy, orthotics, neurotoxic drug avoidance, gene-specific clinical trials, surveillance for associated features

    How GJB1 is laid out

    • Coding sequence
    • Untranslated region
    • Intron
    • Direction of transcription
    • Known disease-causing sites
    Chromosome X, with a bracket where GJB1 sits. GJB1 and 18 genes near it on chromosome X, from 70,724,370 to 71,724,369.Chromosome XXq13.1p22.33p22.32p22.31p22.2p22.13p22.12p22.11p21.3p21.2p21.1p11.4p11.3p11.23p11.22p11.21p11.1q11.1q11.2q12q13.1q13.2q13.3q21.1q21.2q21.31q21.32q21.33q22.1q22.2q22.3q23q24q25q26.1q26.2q26.3q27.1q27.2q27.3q2870.8 Mb71 Mb71.2 Mb71.4 Mb71.6 MbTEX11: 70,528,940–70,908,711, reverse strandTEX11SLC7A3: 70,925,556–70,931,149, reverse strandSLC7A3SNX12: 70,963,111–71,073,426, reverse strandSNX12FOXO4: 71,095,839–71,103,535, forward strandCXorf65: 71,103,889–71,106,788, reverse strandCXorf65: 71,103,987–71,111,575, reverse strandIL2RG: 71,107,404–71,112,108, reverse strandIL2RGMED12: 71,118,543–71,144,103, forward strandMED12NLGN3: 71,143,286–71,175,306, forward strandNLGN3GJB1: 71,223,224–71,225,516, forward strandGJB1ZMYM3: 71,239,617–71,255,269, reverse strandZMYM3NONO: 71,254,270–71,301,522, forward strandNONOITGB1BP2: 71,301,717–71,305,371, forward strandITGB1BP2TAF1: 71,366,129–71,532,374, forward strandTAF1OGT: 71,533,068–71,575,892, forward strandOGTGCNA: 71,578,436–71,613,590, forward strandGCNACXCR3: 71,615,912–71,618,545, reverse strandCXCR3CXorf49C: 71,667,542–71,671,527, forward strandCXorf49CCXorf49: 71,714,369–71,718,307, reverse strandCXorf49Diagram of GJB1: 2 exons on the forward strand of chromosome XExon 1: 2 known disease-causing sitesExon 2: 97 known disease-causing sitesExon 1: 71,223,224–71,223,335, 112 basesExon 2: 71,223,692–71,225,516, 1,825 bases125′3′

    Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

    Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

    Nearby genes from Ensembl release 116, on GRCh38.

    Exons make up 1.9 kb of the gene's 2.3 kb; 852 of those bases code for the protein.

    How a genome test reads GJB1

    101

    positions in GJB1 where ClinVar classes a change as pathogenic or likely pathogenic

    None of them falls in a region short reads find hard.

    A whole genome covers all 2.3 kb of GJB1, introns included, not only the 1.9 kb of exons.

    Where this comes from

    • HGNC: the gene's symbol, name, other symbols and location.
    • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
    • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
    • The ACMG secondary findings list, SF v3.2.
    • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
    • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
    • Data release 2026.10.16-c6eea6bf.

    Cite this page

    APA

    Dante Labs. (n.d.). GJB1 gene: gap junction protein beta 1. Retrieved 17 October 2026, from https://dantelabs.com/genes/gjb1

    Vancouver

    Dante Labs. GJB1 gene: gap junction protein beta 1 [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/gjb1

    One test. A lifetime of answers.

    From $449Free shipping · Results in 6–8 weeks

    Get my Genome Test