The spectrum of GJB2 mutations in the Iranian population with non-syndromic hearing loss--a twelve year study.
OBJECTIVE
Mutations in GJB2, encoding connexin 26 (CX26), are causally related to autosomal recessive form of non-syndromic hearing loss (NSHL) at the DFNB1 locus and autosomal dominant NSHL at the DFNA3 locus. In this study, we investigated the prevalence of GJB2 mutations in the Iranian deaf population.


METHODS
A total of 2322 deaf probands presenting the ethnically diverse Iranian population were screened for variants in GJB2. All persons were first screened for the c.35delG mutation, as this variant is the most prevalent GJB2-deafness causing mutation in the Iranian population. In all persons carrying zero or one c.35delG allele, exons 1 and 2 were then sequenced.


RESULTS
In total, 374 (~16%) families segregated GJB2-related deafness caused by 45 different mutations and 5 novel variants. The c.35delG mutation was most commonly identified and accounts for ~65% of the GJB2 mutations found in population studied.


CONCLUSIONS
Our data also show that there is a gradual decrease in the frequency of the c.35delG mutation and of GJB2-related deafness in general in a cline across Iran extending from the northwest to southeast.
Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Niloofar
N
Bazazzadegan
Nooshin
N
Nikzat
Zohreh
Z
Fattahi
Carla
C
Nishimura
Nicole
N
Meyer
Shima
S
Sahraian
Payman
P
Jamali
Mojgan
M
Babanejad
Atie
A
Kashef
Hilda
H
Yazdan
Farahnaz
F
Sabbagh Kermani
Maryam
M
Taghdiri
Batool
B
Azadeh
Faezeh
F
Mojahedi
Atefeh
A
Khoshaeen
Haleh
H
Habibi
Farahnaz
F
Reyhanifar
Narges
N
Nouri
Richard J H
RJ
Smith
Kimia
K
Kahrizi
Hossein
H
Najmabadi
D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D003241:Consanguinity; D004252:DNA Mutational Analysis; D034381:Hearing Loss / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D007492:Iran / Q000453:epidemiology; D009154:Mutation; D011110:Polymorphism, Genetic; D015995:Prevalence
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26