title: GJB2 allele variants and the associated audiologic features identified in Chinese patients with less severe idiopathic hearing loss.
abstract: OBJECTIVE
  To explore possible correlations between the genotype of GJB2, the gene that encodes connexin 26 (Cx26), and its related audiogram features in Chinese patients with less severe nonsyndromic hearing loss (HL), we examined the pure tone audiograms and GJB2 coding region allele variants in 236 patients.
  
  
  RESULTS
  Twelve of 34 (35.3%) patients with biallelic GJB2 mutations had totally asymmetric HL, a significantly higher prevalence than in patients with wild-type GJB2 (p = 0.027). In patients with biallelic GJB2 mutations, the percentages of cases with sloping, flat, and differently shaped audiograms between ears were 44.1%, 11.8%, and 35.3%, respectively; however, in patients with wild-type GJB2, the percentages were 72.4%, 3.4%, and 21.1%, respectively. Significant differences were found between patients with wild-type GJB2 and those with biallelic GJB2 mutations (p = 0.013) as well as those with single GJB2 mutations (p = 0.043). Threshold differences between ears were significantly higher in patients carrying GJB2 polymorphisms than in patients with wild-type GJB2 at 250-8000 Hz (p < 0.05). The threshold changes at adjacent octaves showed significant differences between groups at each adjacent frequency from 4000 to 8000 Hz (p = 0.04).
  
  
  CONCLUSIONS
  The patients who carried biallelic pathogenic Cx26 mutations showed asymmetric HL compared with the patients who carried wild-type Cx26. The threshold difference and threshold changes at adjacent octaves between ears were higher in the patients with Cx26 polymorphisms.
authors.affiliation: Department of Otolaryngology, Eye Ear Nose and Throat Hospital of Fudan University, 83 Fen Yang Road, Shanghai, China.
authors.forename: Jianning
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhengmin
authors.initials: Z
authors.lastname: Wang
authors.forename: Wenjia
authors.initials: W
authors.lastname: Dai
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Zeng
authors.forename: Huawei
authors.initials: H
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People / Q000235:genetics*; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000208:ethnology; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006312:Hearing Loss, Bilateral / Q000235:genetics / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26