Background: Hearing Impairment (HI) can have genetic or environmental causes and in some cases, an interplay of both. Genetic causes are difficult to determine as mutations in more than 90 genes have been shown recently to be responsible for HI. Providing a genetic diagnostic test for HI is therefore a challenge especially for ethnic groups where GJB2 mutations are shown to be rare.
Results: Here we show the design and implementation of an amplicon-based targeted sequencing panel that allows the simultaneous sequencing of 87 HI genes. Mutations identified included known pathogenic mutations and novel variants with unknown significance. The diagnostic rate of this panel is 28 % when only pathogenic variants were reported. However, an additional 28 % harbored recurrent combinations of novel or rare single nucleotide variants in the OTOF or PCDH15 genes. Such combinations were not identified in healthy individuals.
Conclusions: Targeted sequencing approach is a very useful strategy for the identification of mutations affecting the HI genes because of its relatively fast turn-around time and cost effectiveness compared to whole-exome sequencing. Further novel or rare variants could be identified by implementing a large-scale screening of HI using our panel which will eventual lead to a higher diagnostic rate.
Keywords: Hearing impairment; NGS; Saudi Arabia; Targeted sequencing.