[The results of audiological examination of children presenting with sensorineural loss of hearing due to GJB2 gene mutations during the first year of life].

One of the topical problems of modern pediatric audiology is early diagnostics of congenital sensorineural loss of hearing in children and their timely rehabilitation. The objective of the present study was to obtain audiological characteristics of sensorineural hearing impairment associated with GJB2 gene mutations in children during the first year of life. The methods used were registration of short-latency auditory evoked potentials (slAEP) and the otoacoustic emission (OAE) techniques. The study included 66 children at the age of several months presenting with bilateral sensorineural loss of hearing who were available for the examination by an otorhinolaryngologist, tympanometry, slAEP recording, delayed EOAE (dEOAE) and distortion-product frequency OAE (dpOAE) techniques, and genetic counseling. The examination was carried out in duplicate, with an interval of 3 months. The genotype containing GJB2 gene mutations was identified in 47 (71.2%) children. The 35delG mutation was found in 41; in 31 of them it occurred in the homozygous state and in 10 in the heterozygous state. In the latter group, 8 children had the 35delG mutation in the compound heterozygous state together with one more mutation. Six children turned out to carry a pathological genotype with other GJB2 gene mutations. It was shown that OAE fails to be recorded in most patients with hearing impairment due to GJB2 gene mutations during the first months of life. The authors conclude that these mutations usually lead to the development of persistent bilateral symmetric sensorineural loss of hearing.