In silico and in vivo analyses of novel variants identified by Whole Exome Sequencing in Argentinean deaf patients: to be or not be pathogenic

PAULA BUONFIGLIO; CARLOS DAVID BRUQUE; ERNESTO GOLDSCHMIDT; VANESA LOTERSZTEIN; PAOLA PLAZAS; ANA BELÉN ELGOYHEN; VIVIANA DALAMON

Congreso; European Human Genetics Virtual Conference; 2020

Hereditary hearing loss is the most common sensory disorder that affects 1:500 newborn children. It is a heterogeneous disease and more than 150 genes have been described. This complexity led us to design a multistep diagnosis strategy, using Whole Exome Sequencing Technique (WES), in order to identify the causative mutations of hereditary hearing loss in our population.1250 patients were analyzed for GJB2 and GJB6 frequent mutations by Sanger Sequencing. After excluding them, WES technique was performed in 29 families with syndromic and non-syndromic hearing loss. A filtering process was applied in order to collect probable pathogenic mutations which were studied via bioinformatic analysis. Additionally, conservation studies, structure and protein domain analysis were carried out, as well as in-vivo functional validation. Approximately 300/1250 (25%) of patients were diagnosed by GJB2/GJB6 analysis. 13/29 were diagnosed by WES (45%), identifying 23 causative mutations (11 novel and 12 reported). Mutation functional impact analysis with Bioinformatic Tools revealed that identified mutations were damaging to the proteins. Functional in vivo analysis using Zebra fish models are under way. In the present study we showcase clear-cut results using WES analysis as a successful strategy for the genetic diagnosis of hearing loss. Our algorithm is advantageous for large-scale molecular analysis. These findings clearly highlight the importance of genetic studies followed by in silico and in vivo validation to better understand the genetic basis of hereditary hearing loss.