Abstract
BackgroundEvery year, 30,000 babies are born with congenital hearing impairment in China. The molecular etiology of hearing impairment in the Chinese population has not been investigated thoroughly. To provide appropriate genetic testing and counseling to families, we performed a comprehensive investigation of the molecular etiology of nonsyndromic deafness in two typical areas from northern and southern China.MethodsA total of 284 unrelated school children with hearing loss who attended special education schools in China were enrolled in this study, 134 from Chifeng City in Inner Mongolia and the remaining 150 from Nangtong City in JiangSu Province. Screening was performed for GJB2, GJB3, GJB6, SLC26A4, 12S rRNA, and tRNAser(UCN) genes in this population. All patients with SLC26A4 mutations or variants were subjected to high-resolution temporal bone CT scan to verify the enlarged vestibular aqueduct.ResultsMutations in the GJB2 gene accounted for 18.31% of the patients with nonsyndromic hearing loss, 1555A>G mutation in mitochondrial DNA accounted for 1.76%, and SLC26A4 mutations accounted for 13.73%. Almost 50% of the patients with nonsyndromic hearing loss in these typical Chinese areas carried GJB2 or SLC26A4 mutations. No significant differences in mutation spectrum or prevalence of GJB2 and SLC26A4 were found between the two areas.ConclusionIn this Chinese population, 54.93% of cases with hearing loss were related to genetic factors. The GJB2 gene accounted for the etiology in about 18.31% of the patients with hearing loss, SLC26A4 accounted for about 13.73%, and mtDNA 1555A>G mutation accounted for 1.76%. Mutations in GJB3, GJB6, and mtDNA tRNAser(UCN) were not common in this Chinese cohort. Conventionally, screening is performed for GJB2, SLC26A4, and mitochondrial 12S rRNA in the Chinese deaf population.
Highlights
Hearing impairment is the most common neurosensory disorder in humans, with an incidence of approximately one in 1000 children worldwide
Some mutational hotspots involved in inherited hearing impairment, such as GJB2 235 delC, SLC26A4 IVS7-2A>G, and mitochondrial DNA 1555A>G, have been reported in Chinese deaf populations, the molecular etiology of deafness in Chinese children has not been investigated systematically, and effective genetic evaluation strategies for hearing impairment are not available in most areas of China
GJB2 gene mutations Sequence analysis of the GJB2 gene indicated that 51 patients carried two confirmed pathogenic mutations, and 1 patient had an R75W mutation, which has been reported to cause autosomal dominant syndromic deafness with palmoplantar keratoderma [44] (Table 1)
Summary
Hearing impairment is the most common neurosensory disorder in humans, with an incidence of approximately one in 1000 children worldwide. In China, it has been estimated that 30,000 babies are born with congenital hearing impairment per 20 million live births every year [2]. Some mutational hotspots involved in inherited hearing impairment, such as GJB2 235 delC, SLC26A4 IVS7-2A>G, and mitochondrial DNA 1555A>G, have been reported in Chinese deaf populations, the molecular etiology of deafness in Chinese children has not been investigated systematically, and effective genetic evaluation strategies for hearing impairment are not available in most areas of China. Comprehensive genetic analysis of deaf children in different regions of China should be performed to obtain epidemiological information to provide effective genetic testing and accurate counseling. To provide appropriate genetic testing and counseling to families, we performed a comprehensive investigation of the molecular etiology of nonsyndromic deafness in two typical areas from northern and southern China
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
