Common molecular etiology of nonsyndromic hearing loss in 484 patients of 3 ethnicities in northwest China

Abstract

Conclusions: In the study population in northwest China, a total of 33.06% of deaf patients have inherited hearing impairment caused by GJB2, SLC26A4, and mtDNA 1555A>G mutations. The mutation frequencies of GJB2, SLC26A4, and mtDNA 1555A>G genes were 16.12%, 10.54%, and 6.4%, respectively, in our study cohort. Thus, screening is conventionally performed for GJB2, SLC26A4, and mtDNA 1555A>G in these populations. Objective: This study aimed to investigate the mutations of GJB2, mitochondrial DNA 12S rRNA1555A>G, and SLC26A4 genes in Han Chinese, Hui people, and Tibetan ethnicities in patients with nonsyndromic hearing loss (NSHL) in northwest China. Methods: A total of 484 unrelated subjects with hearing loss who attended special education schools in northwest China were enrolled in this study. Three prominent deafness-related genes, GJB2, SLC26A4, and mtDNA 1555A>G, were screened for mutations in our study cohort. Results: The mutation frequencies of GJB2, SLC26A4, and mtDNA 1555A>G genes were 16.12%, 10.54%, and 6.4%, respectively. The prevalence of GJB2 mutations was 17.52%, 15.35%, and 11.43% in Han Chinese, Hui people, and Tibetan participants, respectively. c.235delC was the most prevalent mutation, accounting for 65.71% of all GJB2 mutant alleles. The prevalence of SLC26A4 mutations was 12.39%, 8.84%, and 8.57% in Han Chinese, Hui people, and Tibetan participants, respectively. The c.919-2 A>G mutation was the most common form, accounting for 60.47% of all SLC26A4 mutant alleles. The prevalence of the homoplasmic mtDNA 1555A>G mutation was 8.97%, 3.72%, and 5.71% in Han Chinese, Hui people, and Tibetan participants, respectively, which represents a statistically significant difference between the Han Chinese and Hui people (χ² = 5.118, p < 0.05).

Keywords:

• Deafness-related genes
• GJB2
• SLC26A4
• mtDNA1555A>G
• Han Chinese
• Hui people
• Tibetan

Acknowledgments

We would like to thank all the patients and their parents. This research was supported by the National Natural Science Foundation of China (grant no. 81172765), Gansu Young and Middle-Aged Scientists (no. 0711RJYA009).

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