Suspension array-based deafness genetic screening in 53,033 Chinese newborns identifies high prevalence of 109 G>A in GJB2

Abstract

ObjectivesMore than 50% of congenital hearing loss is attributed to genetic factors. Data of gene mutation associated with hearing loss from large population studies in Chinese population are scarce. In this study, we conducted a comprehensive newborn genetic screening in China to establish the carrier frequency and mutation spectrum of deafness-associated genes. MethodsA total of 53,033 newborns were screened for hearing defects associated mutations. Twenty hot spot mutations in GJB2, GJB3, SLC26A4 and mitochondria12S rRNA were examined using suspension array analysis. Results14,185 newborns (26.75%) were identified with at least one mutated allele. 872 (1.64%) neonates carried homozygous mutations including 112 (0.21%) mitochondrial DNA homoplasmy, 228 (0.43%) were compound heterozygotes, and 11,985 (22.59%) were heterozygotes including 11 (0.02%) mitochondrial DNA heteroplasmy. Top five mutations included 109 G > A, 235 delC, 299–300 delAT in GJB2, IVS7-2 A > G in SLC26A4 and 1555 A > G in mitochondria12S rRNA. Notably, a total of 10,995 neonates (20.73%) carried 109 G > A in GJB2. Moreover, the allele frequencies of 109 G > A were detected 11.61% in Guangdong, 10.44% in Sichuan and 2.88% in Shandong, respectively, a significant difference in prevalence among these geographic regions (p<0.01). In addition, the high frequency of 109 G > A in GJB2 was confirmed by a TaqMan probe-based qPCR assay. Very recently, the ClinGen Hearing Loss Expert Panel reached a consensus and confirmed its pathogenic role in hearing impairment. ConclusionWe delineated the mutation profile of common deafness-causing genes in the Chinese population and highlighted the high prevalence of 109 G > A pathogenic mutation. Our study may facilitate early diagnosis/intervention and genetic counseling for hearing impairment in clinical practice.