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

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 1555AG mutations. The mutation frequencies of GJB2, SLC26A4, and mtDNA 1555AG genes were 16.12%, 10.54%, and 6.4%, respectively, in our study cohort. Thus, screening is conventionally performed for GJB2, SLC26A4, and mtDNA 1555AG in these populations.This study aimed to investigate the mutations of GJB2, mitochondrial DNA 12S rRNA1555AG, and SLC26A4 genes in Han Chinese, Hui people, and Tibetan ethnicities in patients with nonsyndromic hearing loss (NSHL) in northwest China.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 1555AG, were screened for mutations in our study cohort.The mutation frequencies of GJB2, SLC26A4, and mtDNA 1555AG 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 AG mutation was the most common form, accounting for 60.47% of all SLC26A4 mutant alleles. The prevalence of the homoplasmic mtDNA 1555AG 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 (χ(2) = 5.118, p0.05).