Evaluation of GJB2 and GJB6 Mutations in Patients Afflicted with Non-syndromic Hearing Loss

Authors

1 Associate Professor of Otolaryngology, Department of Otolaryngology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

2 Resident of Otolaryngology, Department of Otolaryngology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

3 Professor of Otolaryngology, Department of Otolaryngology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

4 Professor of Medical Genetic, Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

5 Community Medicine Specialist, Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.

6 MSc. in Medical Genetic, Department of Genetics and Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran.

7 Postdoctoral Research Fellow, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran.

Abstract

Background
Non-syndromic hearing loss (NSHL) is assumed as one of the highly prevalent congenital defects in the world. In this regard, gap junction protein beta 2(GJB2), and gap junction protein beta 6(GJB6) mutations are considered as the leading congenital causes of deafness. The present study aimed to assess the prevalence of GJB2 and GJB6 mutations in NSHL cases.
Materials and Methods
This cross-sectional study was implemented from Jan. 2015 to Sep. 2017 at Alzahra Hospital (Isfahan, Iran).46 patients afflicted with NSHL were recognized and recruited by physicians. Heparinized blood was collected and DNA of each participant was extracted. Genetic analysis of GJB2 and GJB6 genes was performed using PCR and GAP-PCR methods respectively.
Results: 35delG mutation had the highest prevalence with allelic frequency of 6.12%. The allelic frequencies of 35delG, and delE120 were 6(6.12%), and 3(3.06%), respectively. Allelic frequency of W77R, Y65H, G160, and R127H was 2(2.04%) for each of them. In addition, 2 patients were heterozygous for p.V153I rare polymorphism (2.04%).
Conclusion
Overall, the present study indicated that 35delG mutation could be considered as the foremost causative factor of NHCL.  GJB2 mutations were highly prevalent among NSHL cases (23.9%). As a result, the mutation analysis of this gene could be appropriately used for prevention and early diagnosis of NSHL.

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