Prevalence of the 35delG mutation in the GJB2 gene of patients with nonsyndromic hearing loss from Croatia.
The aim of this study was to investigate the allelic frequency of 35delG mutation in patients with recessive, nonsyndromic hearing loss (NSHL) compared to normal hearing individuals in the Croatian population. For this purpose, we analyzed 27 unrelated individuals with nonsyndromic hearing loss and 342 healthy individuals. The method we used is based on the principle of polymerase chain reaction (PCR)-mediated, site-directed mutagenesis, followed by a BsiYI digestion. Among patients with NSHL, the 35delG mutation was found on 51.85% alleles. Carrier frequency among healthy control individuals was 1 in 68.4 (1.5%). The patients, found to be wild-type, either in heterozygous or homozygous form, were further tested by direct sequencing. Among them, two different mutations were observed, W24X and 313del14. Relatively high prevalence of 35delG mutation among patients with NSHL indicate that it is an important cause of NSHL in Croatia. Early diagnosis by identification of the 35delG mutation would greatly improve genetic counseling, as well as treatment and management of deafness in Croatia.