Novel Compound Heterozygous MYO15A Splicing Variants in Autosomal Recessive Non-syndromic Hearing Loss

Abstract

Abstract Background:Hereditary hearing loss is ahighly heterogeneous disorder both genetically and clinically. In this study, we aimed to identify the genetic cause of a Chinese family with autosomal recessive nonsyndromic sensorineural hearing loss (ARNSHL). Methods:Clinical information and peripheral blood samples were collected from the proband and its parents. Two-stephigh-throughput next-generation sequencing on theIon Torrent platform was applied to detect mutations as follows. First, long-range PCR was performed to amplify the entire regions of the GJB2, GJB3, SLC26A4 and MT-RNR1 genes, and the products were submitted to next-generation sequencing. Targeted exon sequencing with AmpliSeq technology was further performed to examine another 64 deafness-associated genes. The identified variants and the cosegregationwith disease phenotypes in the family were validated by Sanger sequencing. We then assessed the effect of the mutation on the splicing of the MYO15A gene by bioinformatics prediction and minigene assays. Results:Two candidate MYO15A gene heterozygous splicing mutations, c.6177+1G>T and c.9690+1G>A, were identified in the proband, and these two variants were both annotated as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guidelines. Further bioinformatic analysis predicted that thec.6177+1G>T mutation might cause exon skipping and that the c.9690+1G>A mutation might activate a cryptic splicing donor site in the downstream intronic region. An in vitro minigene assay confirmed the above predictions. Conclusions:We identified a compound heterozygous splicing mutation in the MYO15A gene in a Han Chinese family with ARNSHL. Our results broaden the spectrum of MYO15A mutations, potentially benefiting the early diagnosis, prevention and treatment of the disease.