title: Developing regional genetic counseling for southern Chinese with nonsyndromic hearing impairment: a unique mutational spectrum.
abstract: BACKGROUND
  Racial and regional factors are important for the clinical diagnosis of non-syndromic hearing impairment. Comprehensive genetic analysis of deaf patients in different regions of China must be performed to provide effective genetic counseling. To evaluate the mutational spectrum of south Chinese families, we performed genetic analysis for non-syndromic hearing impairment in this population.
  
  
  METHODS
  Complete clinical evaluations were performed on 701 unrelated patients with non-syndromic hearing impairment from six provinces in south China. Each subject was screened for common mutations, including SLC26A4 c.IVS7-2A > G, c.2168A > G; mitochondrial DNA m.1555A > G, m.1494C > T, m.7444G > A, m.7445A > G; GJB3 c.538C > T, c.547G > A; and WFS1 c.1901A > C, using pyrosequencing. GJB2 and SLC26A4 coding region mutation detection were performed using Sanger sequencing.
  
  
  RESULTS
  Genetic analysis revealed that among the etiology of non-syndromic hearing impairment, GJB2, SLC26A4, and mitochondrial m.1555A > G mutations accounted for 18.0%, 13.1%, and 0.9%, respectively. Common mutations included GJB2 c.235delC, c.109G > A, SLC26A4 c.IVS7-2A > G, c.1229 T > C, and mitochondrial m.1555A > G. The total mutation rate was 45.1% in all patients examined in south China. Overall, the clear contribution of GJB2, SLC26A4, and mitochondrial m.1555A > G to the etiology of the non-syndromic deafness population in south China was 32.0%.
  
  
  CONCLUSIONS
  Our study is the first genetic analysis of non-syndromic hearing impairment in south China, and revealed that a clear genetic etiology accounted for 32.0% of non-syndromic hearing cases in patients from these regions. The mutational spectrum of non-syndromic hearing impairment in the south Chinese population provides useful and targeted information to aid in genetic counseling.
authors.forename: Kaitian
authors.initials: K
authors.lastname: Chen
authors.forename: Ling
authors.initials: L
authors.lastname: Zong
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Xianren
authors.initials: X
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhan
authors.forename: Hui
authors.initials: H
authors.lastname: Cao
authors.forename: Chang
authors.initials: C
authors.lastname: Dong
authors.forename: Haocheng
authors.initials: H
authors.lastname: Tang
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou 510080, People's Republic of China. jhongy@mail.sysu.edu.cn.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D044466:Asian People / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002681:China; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics; D003638:Deafness / Q000235:genetics; D005260:Female; D005817:Genetic Counseling; D018740:Genetic Heterogeneity; D005843:Geography; D006801:Humans; D007223:Infant; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D000076988:Sulfate Transporters; D014723:Vestibular Aqueduct / Q000473:pathology; D055815:Young Adult
chemical_list: D017630:Connexins; D004272:DNA, Mitochondrial; C000607042:GJB2 protein, human; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; C114987:wolframin protein; D000072259:Connexin 26