Allelic heterogeneity among Iranian DFNB7/11 families: report of a new Iranian deaf family with TMC1 mutation identified by next-generation sequencing

Abstract

Conclusion: Co-segregation of c.2030T>C mutation with hearing loss in an Iranian family and absence of this mutation in 100 Iranian controls confirms the pathogenicity of this mutation. Allelic heterogeneity among Iranian DFNB7/11 families has been shown by the identification of six different mutations in eight families. Objectives: Transmembrane channel-like 1 (TMC1) gene encodes an integral membrane protein such that its mutations can cause DFNB7/11 hearing loss. To date, several TMC1 mutations have been reported from Iran. Here we report a new DFNB7/11 Iranian family with an unreported TMC1 mutation in Iran. Methods: A total of 66 genes related to hearing loss were analyzed using the OtoSCOPE platform in an affected member of an Iranian deaf family (Irn-Deaf-6866). Sanger sequencing was performed to confirm next-generation sequencing findings. Results: A mutation, c.2030T>C, was identified in exon 21 of the TMC1 gene in the investigated member of the family. Sequencing results in all members of the family confirmed association of this mutation with hearing loss. None of 100 ethnically matched healthy controls had this mutation.

Keywords:

• Autosomal recessive non-syndromic hearing loss
• deafness
• c.2030T>C
• OtoSCOPE platform

Acknowledgments

This study is part of a PhD thesis and was financially supported by the Kawsar Human Genetics Research Center and Pasteur Institute of Iran. The authors would like to gratefully thank the Irn-Deaf-6866 family who took the time to contribute to this study.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper.