Reevaluating the splice-altering variant in TECTA as a cause of nonsyndromic hearing loss DFNA8/12 by functional analysis of RNA

PURPOSE: The aim of this study was to determine the genetic cause of early onset autosomal dominant hearing loss segregating in five-generation kindred of Chinese descent and provide preimplantation genetic testing (PGT)for them. METHODS: Clinical examination, pedigree analysis and exome sequencing were carried out on the family. Minigene-based splicing analysis, in vivo RNA analysis and protein structure prediction by molecular modeling were conducted on the candidate variant. PGT for the causative variation and chromosome aneuploidis based on SNP analysis has been used for avoidance of hearing loss in this family. RESULTS: All the affected individuals presented with moderate down-sloping hearing loss and whole-exome sequencing identified a novel splice-site variant c.5383+6T>A in the tested subjects within the TECTA locus. Genotyping of all the 32 family members confirmed segregation of this variant and the hearing loss phenotype in the extended family. Functional analysis of RNA and molecular modeling indicates that c.5383+6T>A is a pathogenic splice-site variant and should be considered as genetic cause of the hearing loss. Furthermore, a successful singleton pregnancy with no variation in TECTA c.5383+6 was established and a healthy male child was born by PGT. CONCLUSION: We have identified a novel variant c.5383+6T>A in TECTA ZA-ZP inter-domain, which could be attributable to the early-onset autosomal dominant hearing loss. The implications of our study are valuable in elucidating the disrupted RNA splicing and uncovering the genetic cause of hearing loss with TECTA pathogenic variants, as well as providing reproductive approaches to healthy offspring.