High frequency of heterozygosity in GJB2 mutations among patients with non-syndromic hearing loss.
OBJECTIVE
To determine the prevalence of GJB2 mutations among subjects with congenital, non-syndromic, sensorineural hearing loss, within a north Indian population.


METHODS
This was a case-control study in which the frequencies of the three most prevalent GJB2 mutations (35delG, W24X and 167delT) were studied. Polymerase chain reaction restriction fragment length polymorphism assays were performed to detect these mutations. The entire coding region of the GJB2 gene was sequenced in all patients, and also in any of their family members who showed GJB2 mutations.


RESULTS
The 35delG mutation was found to be the most prevalent mutation (21 per cent), followed by the W24X mutation (7 per cent). This is the first report of the 35delG mutation in an Indian population. One patient was a compound heterozygote for 35delG/W24X. The 167delT mutation was not observed in any patient.


CONCLUSIONS
These findings challenge the classical view that the W24X variant of the GJB2 gene represents a single 'founder' mutation.
Department of Otolaryngology and Head and Neck Surgery, Post-Graduate Institute of Medical Education and Research, Chandigarh, India.
G
G
Khandelwal
S
S
Bhalla
M
M
Khullar
N K
NK
Panda
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D018389:Codon, Nonsense / Q000235:genetics*; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D006319:Hearing Loss, Sensorineural / Q000151:congenital / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D007194:India; D007223:Infant; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D055815:Young Adult
D018389:Codon, Nonsense; D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26