[Analysis of genotypes and audiological characteristics of children with SLC26A4 gene pathogenic mutations]

Objective:To explore the correlation of SLC26A4 genotype and audiology.Method:The subjects were 70 children aged 0 to 7 years old, who were admitted to otological outpatient department.All subjects received nine crystal hereditary deafness gene chip and confirmed by (or)SLC26A4 gene full coding region detection.The patients were diagnosed as homozygous or compound heterozygous mutations.At the same time,acoustic immittance,auditory brainstem response, auditory steady state response and pediatric behavior audiometry, newborn hearing screening and other audiological tests were displayed. According to the genotype, the subjects were divided into two groups: group A (SLC26A4 gene homozygous mutation) in 40 cases, group B (SLC26A4 gene compound heterozygous mutation) in 30 cases. The frequency of SLC26A4 gene mutation, the two groups of genotypes and hearing screening results,the degree of hearing loss and audiometric configurations were analyzed statistically. Result: In 70 patients, the top 4 of the 70 patients with high frequency of mutations were IVS7-2A> G(76.43%), 2168A> G(15.00%), 1226G> A(2.86%) and 2000T> C(2.16%), respectively. 34.29% of newborns passed hearing screening with single or double ears, among which group A and group B were 32.50% and 36.67%,respectively. There was no statistically significant difference between two groups in hearing screening. The degree of hearing loss in group A(56.25%) and group B(48.33%) were mainly profound and there was no significant difference between them. The audiometric configurations: group A(60.00%) was mainly high frequency loss type, while group B(55.00%) was mainly flat type. The difference between them was statistically significant.Conclusion:The mutation sites of SLC26A4 gene were mainly IVS7-2A> G, and the degree of hearing loss was mostly profound. To the audiometric configurations,SLC26A4 gene homozygous mutant were mainly high frequency loss type, while SLC26A4 gene compound heterozygous mutant were mainly flat type. 34.29% children passed universal newborn hearing screening with one ear at least, which indicates SLC26A4 gene mutations can result in late-onset hearing loss, so those patients should be attached great importance..