The genetic bases for non-syndromic hearing loss among Chinese

Abstract

Deafness is an etiologically heterogeneous trait with many known genetic, environmental causes or a combination thereof. The identification of more than 120 independent genes for deafness has provided profound new insights into the pathophysiology of hearing. However, recent findings indicate that a large proportion of both syndromic and non-syndromic forms of deafness in the Chinese population are caused by defects in a small number of genes. Studies of the genetic epidemiology and molecular genetic features revealed that there is a clear relevance of genes causing deafness in Chinese deaf patients as well as a unique spectrum of common and rare deafness gene mutations in the Chinese population. This review is focused on the genetic aspects of non-syndromic and mitochondrial deafness, in which unique molecular genetic features of hearing impairment have been identified in the Chinese population. The current China population is approximately 1.3 billion. It is estimated that 30 000 infants are born with congenital sensorineural hearing loss each year. Better understanding of the genetic causes of deafness in the Chinese population is important for accurate genetics counseling and early diagnosis for timely intervention and treatment options.

Genetic causes of nonsyndromic hearing loss in Iran in comparison with other populations

“…9 Recently, the genetic causes of NSHL in Jews, Japanese and Chinese populations have been described. [10][11][12] In this survey, we emphasized the importance of identifying the genetic bases of NSHL and summarized the published data on the frequency of gene mutations in various loci studied in Iran; we provided counseling criteria for the patients. The distribution of the gene mutations was also shown.…”

Mitochondrial DNA Mutation Screening in an Ethnically Diverse Nonsyndromic Deafness Cohort

“…The prevalence of the A1555G mutation varies in nonsyndromic hearing-impaired populations by ethnicity: 2.9%-5.3% in Asian patients; 0.6%-2.5% in Caucasian deaf populations (Ouyang et al, 2009). In our study, the 1555A > G mutation was found in 0.9% (2/217) patients as a homoplasmic mutation, and at least one patient had a significant history of ototoxic medication exposure.…”

“…The mitochondrial tRNA Ser (UCN) (MTTS1) gene appears to be a significant mitochondrial DNA (mtDNA) mutation locus associated with nonsyndromic sensorineural hearing loss (NSHL). Four deafness-associated mutations, A7445G, 7472insC, T7510C, and T7511C, have been identified in this gene (Ouyang et al, 2009).…”

“…Worldwide, congenital deafness occurs in *1 in 1000 live births, and more than half of these cases are hereditary (Morton, 1991). Sensorineural hearing loss (SNHL) is present in 42% to 70% of individuals with mitochondrial disorders and can be syndromic or nonsyndromic (Ouyang et al, 2009).…”

“…The homoplasmic A1555G mutation of this ribosomal RNA (rRNA) has been associated with aminoglycoside-induced and NSHL in many families of different ethnicities (Ouyang et al, 2009).…”