Brief Report of Variants Detected in Hereditary Hearing Loss Cases in Iran over a 3-Year Period

Abstract

Background: Diagnosis of hereditary hearing loss (HHL) as a heterogeneous disorder is very important espe-cially in countries with high rates of consanguinity where the autosomal recessive pattern of inheritance is preva-lent. Techniques such as next-generation sequencing, a comprehensive genetic test using targeted genomic en-richment and massively parallel sequencing (TGE + MPS), have made the diagnosis more cost-effective. The aim of this study was to determine HHL variants with comprehensive genetic testing in our country. Methods: Fifty GJB2 negative individuals with HHL were referred to the Kariminejad-Najmabadi Pathology and Genetics Center, Tehran, one of the reference diagnostic genetic laboratories in Iran, during a 3-year period between 2014 and 2017. They were screened with the OtoSCOPE test, the targeted genomic enrichment and massively parallel sequencing (TGE + MPS) platform after a detailed history had been taken along with clinical evaluation. Results: Among 32 out of 50 GJB2 negative patients (64%), 34 known pathogenic and novel variants were de-tected of which 16 (47%) were novel, identified in 10 genes of which the most prevalent were CDH23, MYO7A and MYO15A. Conclusion: These results provide a foundation from which to make appropriate recommendations for the use of comprehensive genetic testing in the evaluation of Iranian patients with hereditary hearing loss.

Keywords

• OtoSCOPE
• Hereditary hearing loss
• Novel variant
• Known variant