title: Common molecular etiology of patients with nonsyndromic hearing loss in Tibetan, Tu nationality, and Mongolian patients in the northwest of China.
abstract: CONCLUSIONS
  In the northwest of China, the prevalence of mutations of the three prominent deafness-related genes, GJB2, SLC26A4, and mitochondrial DNA (mtDNA) 12S rRNA, among Tibetan, Tu nationality, and Mongolian subjects is high, at 19%, 28.57%, and 21.05%, respectively. Molecular genetic screening for these mutations and genetic counseling are effective methods to prevent the occurrence of hereditary hearing loss.
  
  
  OBJECTIVE
  To analyze the prevalence of the three common deafness genes GJB2, mtDNA, and SLC26A4 gene mutations in Tibetan, Tu nationality, and Mongolian patients with nonsyndromic hearing impairment in the Northwest region of China.
  
  
  METHODS
  Genomic DNA was extracted from a total of 189 Tibetan, Tu nationality, and Mongolian probands from the northwest of China. PCR and direct sequencing were used to analyze the coding region of GJB2, mtDNA, and SLC26A4 genes.
  
  
  RESULTS
  The mutant allele rate of GJB2 gene was 6.2% in Tibetan and 11.22% in Tu nationality patients, c.235delC was the most prevalent mutation, accounting for 75% of the mutant GJB2 alleles. Mutant allele frequency of SLC26A4 in Tibetan, Tu nationality, and Mongolian subjects was 4.54%, 6.12%, and 15.79% respectively; p.IVS7-2A>G was the most common form. Mongolian cases were significantly higher than Tibetan cases (χ² = 7.281, p = 0.007 and p < 0.05). mtDNA A1555G mutation was detected in six Tibetan, five Tu nationality, and one Mongolian subject; one Tibetan patient carried the C1494T mutation.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Second Hospital of Lanzhou University, China.
authors.forename: Xiao-Long
authors.initials: XL
authors.lastname: Yang
authors.forename: Xu
authors.initials: X
authors.lastname: Bai-Cheng
authors.forename: Xing-Jian
authors.initials: XJ
authors.lastname: Chen
authors.forename: Bian
authors.initials: B
authors.lastname: Pan-Pan
authors.forename: Ma
authors.initials: M
authors.lastname: Jian-Li
authors.forename: Liu
authors.initials: L
authors.lastname: Xiao-Wen
authors.forename: Zhe-Wen
authors.initials: ZW
authors.lastname: Zhang
authors.forename: Du
authors.initials: D
authors.lastname: Wan
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Zhu
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Guo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D003638:Deafness / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D008875:Middle Aged; D008986:Mongolia / Q000453:epidemiology / Q000208:ethnology; D009154:Mutation; D011110:Polymorphism, Genetic; D012335:RNA, Ribosomal / Q000235:genetics*; D000076988:Sulfate Transporters; D018609:Tibet / Q000453:epidemiology / Q000208:ethnology; D055815:Young Adult
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D026901:Membrane Transport Proteins; D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D000072259:Connexin 26