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Gene

GJB2

gap junction protein beta 2

Summary

Cytogenetic location
13q12.11
Coordinates
Chromosome 13: 20,187,470–20,192,938 (GRCh38)
Exons
2 exons across 5.5 kb
Protein
226 amino acids
Inheritance
Autosomal dominant
Also known as
CX26, NSRD1
Previous symbols
DFNB1, DFNA3
MANE Select transcript
ENST00000382848.5NM_004004.6
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 reports relevant to this gene

  • Hearing Loss and Deafness

    • Autosomal Dominant Nonsyndromic Hearing LossAutosomal dominant

      Autosomal dominant form of nonsyndromic deafness.

      • 3 GenCC submitters rate it definitive or strong
    • Nonsyndromic Genetic Hearing Loss

      One of 97 genes linked to it

      Inherited hearing loss without other medical features, including the common recessive forms caused by GJB2, OTOF, SLC26A4, STRC and many other genes, as well as dominant, X-linked and mitochondrial forms.

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

      Knowing the genetic cause can guide hearing support and cochlear implant decisions, gene-therapy trial eligibility (for example OTOF) and family counselling.

  • Hereditary Palmoplantar Keratodermas and Pachyonychia Congenita

    • Hereditary palmoplantar keratoderma

      Inherited thickening of the palms and soles, including pachyonychia congenita, mal de Meleda, Nagashima-type and Bothnian keratodermas, keratitis-ichthyosis-deafness syndrome, and the CTSC-related Papillon-Lefèvre and Haim-Munk syndromes.

      • 4 GenCC submitters rate it definitive or strong
      What knowing changes

      Diagnosis guides foot care and pain management; for CTSC-related forms early dental treatment protects the teeth, and GJB2-related forms warrant a hearing check.

Inheritance

Autosomal dominant
One changed copy, from either parent, is enough. A parent who has one passes it on to each child with a one-in-two chance.

How GJB2 is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Variants with a page
Chromosome 13, with a bracket where GJB2 sits. GJB2 and 7 genes near it on chromosome 13, from 19,690,204 to 20,690,203.Chromosome 1313q12.11p13p12p11.2p11.1q11q12.11q12.12q12.13q12.2q12.3q13.1q13.2q13.3q14.11q14.12q14.13q14.2q14.3q21.1q21.2q21.31q21.32q21.33q22.1q22.2q22.3q31.1q31.2q31.3q32.1q32.2q32.3q33.1q33.2q33.3q3419.8 Mb20 Mb20.2 Mb20.4 Mb20.6 MbPSPC1: 19,568,249–19,783,019, reverse strandPSPC1ZMYM5: 19,823,482–19,864,935, reverse strandZMYM5ZMYM2: 19,958,673–20,091,856, forward strandZMYM2GJA3: 20,138,252–20,161,615, reverse strandGJA3GJB2: 20,187,470–20,192,938, reverse strandGJB2GJB6: 20,221,962–20,232,450, reverse strandGJB6CRYL1: 20,403,666–20,525,893, reverse strandCRYL1IFT88: 20,566,600–20,691,697, forward strandIFT88Diagram of GJB2: 2 exons on the reverse strand of chromosome 13Exon 2: 158 known disease-causing sitesExon 1: 1 known disease-causing siteExon 2: 20,187,470–20,189,603, 2,134 bases. 21 variants with a page in exon 2. List themExon 1: 20,192,783–20,192,938, 156 bases215′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 2.3 kb of the gene's 5.5 kb; 681 of those bases code for the protein.

How a genome test reads GJB2

163

positions in GJB2 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 5.5 kb of GJB2, introns included, not only the 2.3 kb of exons.

Variants with a page (22)

The GJB2 variants with a page here, most review stars first. Each page describes ClinVar's public record of the variant, never a result.

VariantHGVS c.Exon or intronPosition (GRCh38)ClinVar classificationReview status
c.-22-2A>CIntron 120,189,605Likely pathogenic3 stars out of 4 reviewed by expert panel
c.1A>GExon 220,189,581Pathogenic3 stars out of 4 reviewed by expert panel
c.1A>TExon 220,189,581Likely pathogenic3 stars out of 4 reviewed by expert panel
c.2T>CExon 220,189,580Pathogenic3 stars out of 4 reviewed by expert panel
c.2T>GExon 220,189,580Pathogenic3 stars out of 4 reviewed by expert panel
c.3G>AExon 220,189,579Pathogenic3 stars out of 4 reviewed by expert panel
E47Kc.139G>AExon 220,189,443Pathogenic3 stars out of 4 reviewed by expert panel
G12Cc.34G>TExon 220,189,548Likely pathogenic3 stars out of 4 reviewed by expert panel
G12Vfs*2c.35delExon 220,189,546Pathogenic3 stars out of 4 reviewed by expert panel
K188Rc.563A>GExon 220,189,019Likely pathogenic3 stars out of 4 reviewed by expert panel

See all 22 GJB2 variants →

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.). GJB2 gene: gap junction protein beta 2. Retrieved 16 October 2026, from https://dantelabs.com/genes/gjb2

Vancouver

Dante Labs. GJB2 gene: gap junction protein beta 2 [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/gjb2

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