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connexin-26; gap junction protein beta-2 (CX26, GJB2)
Function:
- connexin, gap junction protein
Structure:
- belongs to the connexin family, beta-type (group I) subfamily
Compartment:
- cell membrane
- cell junction, gap junction
Polymorphism:
- Thr-34 allele was originally thought to be a cause of hereditary non-syndromic sensorineural deafness (DFNA3 & DFNB1)
Pathology:
- homozygous mutations in the connexin 26 (GJB2) are associated with congenital hearing loss [5]
- heterozygous GJB2 mutations are associated with a thickened epidermis [5]
- defects in GJB2 are the cause of
a) non-syndromic sensorineural deafness autosomal recessive type 1 (DFNB1)
b) autosomal dominant non-syndromic sensorineural deafness type 3 (DFNA3)
c) Vohwinkel syndrome
d) palmoplantar keratoderma with deafness
e) keratitis-ichthyosis-deafness syndrome
f) Bart-Pumphrey syndrome
g) ichthyosis hystrix-like with deafness syndrome
Laboratory:
- GJB2 gene mutation
Properties
GENERAL: connexin
RELATED: GJB2 gene c.35delG mutation
GJB2 gene mutation
CONFIGURATION: hexamer
SIZE: entity length = 226 aa
MW = 26 kD
COMPARTMENT: plasma membrane
MOTIF: cytoplasmic domain {1-20}
transmembrane domain {21-40}
exoplasmic loop {41-75}
transmembrane domain {76-98}
cytoplasmic loop {99-131}
transmembrane domain {132-154}
exoplasmic loop {155-192}
transmembrane domain {193-215}
cytoplasmic domain {216-226}
MISC-INFO: CHANNEL_DIAMETER 1.5-2 NM
CONDUCTANCE 100 PS
References
- Swiss Prot :accession P29033
- Connexin-deafness homepage
http://davinci.crg.es/deafness/
- Hereditary hearing loss homepage; Note: gene page
http://webhost.ua.ac.be/hhh/
- GeneReviews
https://www.genecards.org/cgi-bin/carddisp.pl?gene=GJB2
- D'Adamo P et al.
Does epidermal thickening explain GJB2 high carrier frequency
and heterozygote advantage?
Eur J Hum Genet 2009 Mar; 17:284.
PMID: 19050724
- Kelsell DP et al
Connexin 26 mutations in hereditary non-syndromic sensorineural
deafness.
Nature. 1997 May 1;387(6628):80-3
PMID: 9139825