Genotyping of the congenital hearing loss cases for Cx26 and Cx30 gene mutations

SUMMARYGenotyping for Cx26 and Cx30 Gene Mutations in the cases with CongenitalHearing LossHearing loss is the most commonly shown perception malfunction which affects thementality and education of a person and is shown in the rate of 1 per 1000 newborn.About half of the cases with hearing loss have genetic bases. Mutations in the Cx26(GJB2) and Cx30 (GJB6) gene are the leading genetic causes in the cases withnonsyndromic congenital hearing loss. Cx26 and Cx30 proteins function at the gapjuntions in the cohlea of ear. The defects caused by the mutations of 35delG,167delT (of Cx26 gene) and del(GJB6-D13S1830) (of Cx30 gene) are thought to beaffecting the the circulation of potassium ions and therefore leading to hearing loss insome of the cases with congenital hearing loss. The aim of this study was toinvestigate the Cx26 and Cx30 gene mutations in the cases with congenital hearingloss.A total of 47 cases with congenital hearing loss from Karahisar DeafnessSchool were included in this study. Genotyping were performed for 35delG and167delT mutations of Cx26 and del(GJB6-D13S1830) of Cx30 genes using the PCR-ELISA techniques.According to the results obtained from 47 cases, 35delG mutation wasdetected in 7 cases (~%14,9). Four of these mutations were determined ashomozygot mutant (~%8,5) and of three were determined as heterozygot mutant(~%6,4). 167delT and del(GJB6-D13S1830) mutations were not detected in thesecases.In conclusion, 35delG mutation was determined as the most frequently shownmutation which lead to congenital hearing loss in this study like aveable in literature.Key words: congenital, genetic, hearing loss, Cx26 gene, Cx30 gene, 35delG.