Connexin 26 mutations and nonsyndromic hearing impairment in Northern Finland

• Main Authors: Lopponen, T, Vaisanen, ML, Luotonen, M, Allinen, M, Uusimaa, J, Lindholm, P, Mäki-Torkko, Elina, Vayrynen, M, Lopponen, H, Leisti, J
• Format: Article in Journal/Newspaper
• Language: English
• Published: Lippincott Williams & Wilkins 2003
• Subjects: Otorhinolaryngology; M34T; (GJB2); sensorineural hearing impairment; gap junction protein beta-2 gene; 35delG; connexin 26 (Cx26); Northern Finland
• Online Access: https://lup.lub.lu.se/record/298303

Objective: The aims of the present study were to evaluate the role of the gap junction protein beta-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 I of 26 (12 of 313). Conclusion: 35deIG/35deIG 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.