Prevalence of GJB2 causing recessive profound non-syndromic deafness in Japanese children.
OBJECTIVE
GJB2 (gap junction protein, beta 2, 26kDa: connexin 26) is a gap junction protein gene that has been implicated in many cases of autosomal recessive non-syndromic deafness. Point and deletion mutations in GJB2 are the most frequent cause of non-syndromic deafness across racial groups. To clarify the relation between profound non-syndromic deafness and GJB2 mutation in Japanese children, we performed genetic testing for GJB2.


METHODS
We conducted mutation screening employing PCR and direct sequencing for GJB2 in 126 children who had undergone cochlear implantation with congenital deafness.


RESULTS
We detected 10 mutations, including two unreported mutations (p.R32S and p.P225L) in GJB2. We identified the highest-frequency mutation (c.235delC: 44.8%) and other nonsense or truncating mutations, as in previous studies. However, in our research, p.R143W, which is one of the missense mutations, may also show an important correlation with severe deafness.


CONCLUSIONS
Our results suggest that the frequencies of mutations in GJB2 and GJB6 deletions differ among cohorts. Thus, our report is an important study of GJB2 in Japanese children with profound non-syndromic deafness.
Department of Otorhinolaryngology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan. chieri-h@juntendo.ac.jp
Chieri
C
Hayashi
Manabu
M
Funayama
Yuanzhe
Y
Li
Kazusaku
K
Kamiya
Atsushi
A
Kawano
Mamoru
M
Suzuki
Nobutaka
N
Hattori
Katsuhisa
K
Ikeda
D044466:Asian People / Q000235:genetics; D001299:Audiometry; D002675:Child, Preschool; D015331:Cohort Studies; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D003638:Deafness / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D020022:Genetic Predisposition to Disease / Q000453:epidemiology* / Q000208:ethnology; D005820:Genetic Testing / Q000379:methods*; D005838:Genotype; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D015995:Prevalence; D012720:Severity of Illness Index; D017678:Sex Distribution
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26