title: Identification of both MT-RNR1 m.1555A>G and bi-allelic GJB2 mutations in probands with non-syndromic hearing loss.
abstract: OBJECTIVE
  Mutations in GJB2 and MT-RNR1 are common causes for non-syndromic sensorineural hearing loss (NSHL). In this study, we investigated the co-existence of both MT-RNR1 and bi-allelic GJB2 mutations in a large number of simplex and multiplex probands with NSHL.
  
  
  METHODS
  485 simplex and 134 multiplex probands with NSHL were recruited for mutation screening of GJB2 and MT-RNR1 by bidirectional sequencing. Clinical features of probands with both MT-RNR1 and bi-allelic GJB2 mutations were further analyzed in comparison with extended family members.
  
  
  RESULTS
  MT-RNR1m.1555A>G and bi-allelic GJB2 mutations were both detected in one (0.21%) simplex probands and two (1.49%) multiplex probands. Variable hearing phenotypes were found in a pair of siblings with both MT-RNR1 and bi-allelic GJB2 mutations.
  
  
  CONCLUSIONS
  MT-RNR1 and bi-allelic GJB2 mutations may co-exist not only in multiplex probands but also in simplex probands. The variable hearing phenotypes in closely-related family members may reflect the co-existence of different molecular causes and prompt extended genetic tests.
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Yongchuan
authors: Y
authors: Chai
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Lianhua
authors: L
authors: Sun
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Xiuhong
authors: X
authors: Pang
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Xiaowen
authors: X
authors: Wang
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Dongye
authors: D
authors: Chen
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Ying
authors: Y
authors: Chen
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China. Electronic address: wuhao622@sina.cn.
authors: Hao
authors: H
authors: Wu
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China. Electronic address: yangtfxl@sina.com.
authors: Tao
authors: T
authors: Yang
mesh_terms: D000293:Adolescent; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D005820:Genetic Testing; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D010375:Pedigree; D012335:RNA, Ribosomal / Q000235:genetics*
chemical_list: D017630:Connexins; D004272:DNA, Mitochondrial; C000607042:GJB2 protein, human; D012335:RNA, Ribosomal; D000072259:Connexin 26
keywords: Expression variability; GJB2; MT-RNR1; Mutation; Penetrance; Sensorineural hearing loss