Abstract
The diagnosis of the genetic etiology of deafness contributes to the clinical management of patients. We performed the following four genetic tests in three stages for 52 consecutive deafness subjects in one facility. We used the Invader assay for 46 mutations in 13 genes and Sanger sequencing for the GJB2 gene or SLC26A4 gene in the first-stage test, the TaqMan genotyping assay in the second-stage test and targeted exon sequencing using massively parallel DNA sequencing in the third-stage test. Overall, we identified the genetic cause in 40% (21/52) of patients. The diagnostic rates of autosomal dominant, autosomal recessive and sporadic cases were 50%, 60% and 34%, respectively. When the sporadic cases with congenital and severe hearing loss were selected, the diagnostic rate rose to 48%. The combination approach using these genetic tests appears to be useful as a diagnostic tool for deafness patients. We recommended that genetic testing for the screening of common mutations in deafness genes using the Invader assay or TaqMan genotyping assay be performed as the initial evaluation. For the remaining undiagnosed cases, targeted exon sequencing using massively parallel DNA sequencing is clinically and economically beneficial.