title: Correlation analysis of phenotype and genotype of GJB2 in patients with non-syndromic hearing loss in China.
abstract: BACKGROUND
  Disease-associated mutations in GJB2 gene are one of the major reasons that can cause non-syndromic sensorineural hearing loss (NSHL). GJB2 gene deafness has various clinical phenotypes. This study aims to analyze characteristics and relationships of clinical phenotypes through analyzing 1481 NSHL cases and 190 GJB2 deafness patients (with dual gene mutations).
  
  
  METHODS
  All the patients diagnosed as deaf disease molecular diagnostics were obtained from the people's liberation army general hospital from March 2007 to March 2011. The accession number of GJB2 was NM_004004 in GenBank, and sequence alignment and annotation were performed using GeneTool software.
  
  
  RESULTS
  In NSHL patients, mutated allele frequency in GJB2 was 20.57%, and the preponderant type was c.235delC (11.84%) followed by c.109G>A (3.75%). Mutation rate of double allelic gene was 16.18%, including 8.43% of homozygous mutation rate and 7.75% of recombination heterozygosis mutation. Moreover, auditory threshold of GJB2 biallelic marker was associated with ages of onset, while no significant correlation was detected with disease time and whether the inner ear malformation. Similar clinical phenotype could be detected between patients with c.109G>A dual gene mutation and dual gene mutation. However, in the aspect of hearing impairment, the phenomenon of pathopoiesia caused by mutation of c.109G>A was poorer than the other mutations, and even near those patients without pathogenic mutations.
  
  
  CONCLUSIONS
  Our study further shows the definite relationship of clinical phenotype and genotype in GJB2 gene correlated deafness, and these results can provide basis for revealing pathogenesis, gene diagnosis and consult of deafness. The level of evidence in the study is level 4 (case series).
authors.affiliation: Department of Otolaryngology, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, China.
authors.forename: Zhi-Yao
authors.initials: ZY
authors.lastname: Dai
authors.affiliation: Department of Otolaryngology, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, China.
authors.forename: Bao-Chun
authors.initials: BC
authors.lastname: Sun
authors.affiliation: Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Sha-Sha
authors.initials: SS
authors.lastname: Huang
authors.affiliation: Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Yong-Yi
authors.initials: YY
authors.lastname: Yuan
authors.affiliation: Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Yu-Hua
authors.initials: YH
authors.lastname: Zhu
authors.affiliation: Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Su
authors.affiliation: Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China. Electronic address: daipu301@vip.sina.com.
authors.forename: Pu
authors.initials: P
authors.lastname: Dai
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002681:China; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D005260:Female; D005838:Genotype; D034381:Hearing Loss / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D010641:Phenotype; D055815:Young Adult
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26
keywords: GJB2 gene; Genetic testing; Non-syndromic sensorineural hearing loss; Phenotype