Genetic Aetiology of Nonsyndromic Hearing Loss in Moravia-Silesia.

BACKGROUND AND OBJECTIVE

Hearing loss is the most common sensory deficit in humans. The aim of this study was to clarify the genetic aetiology of nonsyndromic hearing loss in the Moravian-Silesian population of the Czech Republic.

PATIENTS AND METHODS

This study included 200 patients (93 males, 107 females, mean age 16.9 years, ranging from 4 months to 62 years) with nonsyndromic sensorineural hearing loss. We screened all patients for mutations in and the large deletion del(-D13S1830). We performed further screening for additional genes (, , , , , , and ) with Sanger sequencing on a subset of patients that were negative for mutations.

RESULTS

We detected biallelic mutations in 44 patients (22%). Among these patients, 63.6%, 9.1% and 2.3% exhibited homozygous c.35delG, p.Trp24*, and p.Met34Thr mutations, respectively. The remaining 25% of these patients exhibited compound heterozygous c.35delG, c.-23+1G>A, p.Trp24*, p.Val37Ile, p.Met34Thr, p.Leu90Pro, c.235delC, c.313_326del14, p.Ser139Asn, and p.Gly147Leu mutations. We found a monoallelic mutation in 12 patients (6.6%). We found no pathogenic mutations in the other tested genes. One fifth of our cohort had deafness related to mutations. The del(-D13S1830), , , , , , , and mutations were infrequently associated with deafness in the Moravian-Silesian population. Therefore, we suggest that del(-D13S1830) testing should be performed only when patients with deafness carry the monoallelic mutation.