Temporal Bone Abnormalities In Infants And Young Children With Hearing Loss Gene Mutations

Objectives:To determine the incidence of temporal bone abnormalities in infants and young children with sensorineural hearing loss(SNHL) and pathogenic genes.Methods:Total of216cases of bilateral deafness infants and young children were selected. Genomic DNA was extracted from peripheral blood. Common deafness genes were investigated from GJB2of SLC26A4and mitochondrial12SrRNA1555A1494C mutations. Temporal bone CT scan examination of the ear from selected sample, clinical audiological data and follow-up was done.Results:Out of216patients with bilateral hearing loss,27cases had inner ear abnormalities. In genes investigation we found that19(9%) children with pathogenic biallelic GJB2gene mutations and6(3%) children with pathogenic biallelic SLC26A4gene mutations.12SrRNA1555A and1494C mutation was not detected.Conclusions:GJB2mutation79G>A,341A>G and109G>A can be a causative mutation that is often associated with slight/mild sensorineural hearing loss. SLC26A4mutation is the major cause of large vestibular aqueduct and c.919-2A>G is the most common type of mutation. Narrowed internal auditory canal may have correlation with GJB2gene mutations. Objective:To investigate the temporal bone CT, common deafness genes and clinical audiological characteristics of congenital unilateral hearing-impaired in infants and young children.Methods:Total of51cases of unilateral deafness infants and young children were selected. The average age was0.9years. The external ear malformations were excluded. Genomic DNA was extracted from peripheral blood. Common deafness genes were investigated from GJB2of SLC26A4and mitochondrial12SrRNA1555A1494C mutations. Result of temporal bone CT scan examination of the ear from selected sample, clinical audiological data and follow-up was done.Results:There were51cases of unilateral deafness in children among them32%(16/51) temporal bone CT scan was abnormalities. Among abnormal CT scan there were3cases of middle ear malformations,3cases of glomus jugulare high and4cases of vestibular aqueduct expansion was noted. In genes investigation we found that1.9%(1/51) of GJB2gene235delC/79G> A,341A> G disease-causing mutations, accompanied by the cochlea are not developed. Same way,4%(2/51) of SLC26A4gene was pathogenic mutations.12SrRNA1555A and1494C mutation was not detected.Conclusion:Patients with unilateral deafness may be1/3have image changes, including higher incidence of jugular bulb. There was lower incidence of GJB2,12SrRNA1555A and1494C gene mutation in unilateral deafness. Unilateral hearing-impaired children with cochlear malformations may due to GJB2gene mutation.