P. [V27i; E114g] Compound Heterozygous State in Gjb2 Gene Could Be an Indicator of the Severity of Congenital Hearing Loss

Abstract

Hearing loss (HL) is the most common sensory disorder, affecting all age groups, ethnicities, and genders. Several genes responsible for hearing loss are related to ion recycling and homeostasis in the inner ear. Mutations in GJB2 gene, the gene encoding gap junction protein connexin26 (Cx26), are most common detected in patients with congenital, recessively inherited, nonsyndromic HL in humans. In order to investigate the molecular etiology of patients with congenital, recessively inherited, and nonsyndromic HL and healthy individuals as control in a family, they were included in this study. Thus, exons of GJB2 gene were amplified by polymerase chain reaction (PCR) and sequenced. In this family, V27I missense mutation and V27I + E114G compound heterozygosity were detected in the results of sequence analysis. The V27I mutation was found in patient with severe HL and healthy individuals. The V27I + E114G compound heterozygosity was detected only in deaf patients. Based on our data, V27I mutations could be considered as a polymorphism not leading to HL. Since V27I + E114G compound heterozygosity was found only in deaf patients, it could be considered as a contributor of HL severity.