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Connexin 26 mutations and nonsyndromic hearing impairment in Northern Finland

2003; Wiley; Volume: 113; Issue: 10 Linguagem: Inglês

10.1097/00005537-200310000-00018

1531-4995

Tuija Löppönen, Marja‐Leena Väisänen, Mirja Luotonen, Minna Allinen, Johanna Uusimaa, Päivi Lindholm, Elina Mäki‐Torkko, Mirja R.H. Väyrynen, Heikki Löppönen, Jaakko Leisti,

Neuroscience of respiration and sleep

Abstract Objective : The aims of the present study were to evaluate the role of the gap junction protein β‐2 gene ( GJB2 ), encoding connexin 26 ( Cx26 ), in children with moderate to profound prelingual nonsyndromic sensorineural hearing impairment (HI) and to investigate the carrier frequencies of the GJB2 gene mutations in a control population in Northern Finland. Methods : Mutation analysis was performed by direct sequencing and carrier detection by conformation sensitive gel electrophoresis further confirmed by direct sequencing. Results : Cx26 mutations were found in 15 of 71 (21.1%) (67 families) children with HI. Homozygosity for the mutation 35delG was shown to be the cause of HI in 13 of 15 (86.7%) children. Homozygosity for the M34T genotype was found in one child, and compound heterozygosity for the M34T/V37I genotype was found in another. Five families of those with suspected familial HI (29.4%) and six families out of those with sporadic HI (12.0%) had a homozygous or compound heterozygous mutation. The carrier frequency for the mutation 35delG was 1 of 78 (4 of 313) and that for the M34T was 1 of 26 (12 of 313). Conclusion : 35delG/35delG genotype was found to be a significant cause of moderate to profound prelingual nonsyndromic sensorineural HI in Northern Finland. M34T/M34T genotype was seen in only one child, but the carrier frequency of the M34T allele was about three times higher than that of the 35delG mutation.