title: Comprehensive molecular etiology analysis of nonsyndromic hearing impairment from typical areas in China.
abstract: BACKGROUND
  Every 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.
  
  
  METHODS
  A 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.
  
  
  RESULTS
  Mutations 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.
  
  
  CONCLUSIONS
  In 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.
authors.affiliation: Department of Otolaryngology, PLA General Hospital, Beijing, PR China. yyymzh@163.com
authors.forename: Yongyi
authors.initials: Y
authors.lastname: Yuan
authors.forename: Yiwen
authors.initials: Y
authors.lastname: You
authors.forename: Deliang
authors.initials: D
authors.lastname: Huang
authors.forename: Jinghong
authors.initials: J
authors.lastname: Cui
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.forename: Dongyang
authors.initials: D
authors.lastname: Kang
authors.forename: Huijun
authors.initials: H
authors.lastname: Yuan
authors.forename: Dongyi
authors.initials: D
authors.lastname: Han
authors.forename: Pu
authors.initials: P
authors.lastname: Dai
mesh_terms: D044466:Asian People / Q000235:genetics*; D002648:Child; D002681:China; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics; D005838:Genotype; D034381:Hearing Loss / Q000151:congenital / Q000209:etiology / Q000235:genetics; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics; D009154:Mutation; D011110:Polymorphism, Genetic; D012335:RNA, Ribosomal / Q000235:genetics; D012362:RNA, Transfer, Ser / Q000235:genetics; D000076988:Sulfate Transporters; D013577:Syndrome; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D013963:Thyroid Hormones / Q000032:analysis; D014463:Ultrasonography
chemical_list: D017630:Connexins; D004272:DNA, Mitochondrial; C000607042:GJB2 protein, human; D026901:Membrane Transport Proteins; D012335:RNA, Ribosomal; D012362:RNA, Transfer, Ser; C075526:RNA, ribosomal, 12S; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D013963:Thyroid Hormones; D000072259:Connexin 26