Analysis of genotypes and hearing phenotypes of mutation infants with deafness / 临床耳鼻咽喉头颈外科杂志

ABSTRACT

The aim of this study is to explore the genotype and hearing phenotype of deaf infants with mutation of gene. Subjects were 121 infants with gene mutations who were treated in the Children's Hearing Diagnosis Center of Beijing Tongren hospital. All subjects were accepted to undertake the universal newborns hearing screening（UNHS） and series of objective audiometry, including auditory brainstem response, distortion product otoacoustic emission, auditory steady-state response and other audiological tests. All subjects were screened for nine pathogenic variants in four genes or all exons of the gene, and then were diagnosed as infants with gene mutations. Initially, analyzing their genotypes and hearing phenotypes generally. Then, the subjects were divided into two groups according to the genotypes T/T group（truncated/truncated mutations, 89 cases） and T/NT group（truncated/non-truncated mutations, 32 cases）. Chi-square test was used to analyze the results of UNHS, hearing degree, audiogram patterns and symmetry/asymmetry of binaural hearing phenotype. Eventually, analyzing the results of UNHS. The most common truncated mutation was c.235delC（64.88%, 157/242） and the most common non-truncated mutation was c.109G>A（11.16%, 27/242）. The homozygous mutation of c.235delC/c.235delC was the dominant in T/T group（38.84%, 47/121）, and the compound heterozygous mutation of c.235delC/c.109G>A was the dominant in T/NT group（18.18%, 22/121）. 81.82%（99/121） of subjects failed in UNHS, including 74.38%（90/121） with bilateral reference, 7.44%（9/121） with a single pass. The refer rate of UNHS of group T/T and T/NT were 86.52%（77/89） and 68.75%, respectively. There was a statistically significant difference between the two groups（0.05）. In this study, c.235delC/c.235delC homozygous mutation was dominant in T/T group and c.235delC/c.109G>A heterozygous mutation was dominant in T/NT Group. The hearing phenotypes in T/T group were mostly bilateral asymmetric severe hearing loss, and those in T/NT Group were bilateral symmetric mild to moderate hearing loss, special attention should be paid to the audiological characteristics of different genotypes.