title: The search of a genetic basis for noise-induced hearing loss (NIHL).
abstract: OBJECTIVE
  Knowledge about the genetic factors responsible for noise-induced hearing loss (NIHL) is still limited. This study investigated whether genetic factors are associated or not to susceptibility to NIHL.
  
  
  METHODS
  The family history and genotypes were studied for candidate genes in 107 individuals with NIHL, 44 with other causes of hearing impairment and 104 controls. Mutations frequently found among deaf individuals were investigated (35delG, 167delT in GJB2, Δ(GJB6- D13S1830), Δ(GJB6- D13S1854) in GJB6 and A1555G in MT-RNR1 genes); allelic and genotypic frequencies were also determined at the SNP rs877098 in DFNB1, of deletions of GSTM1 and GSTT1 and sequence variants in both MTRNR1 and MTTS1 genes, as well as mitochondrial haplogroups.
  
  
  RESULTS
  When those with NIHL were compared with the control group, a significant increase was detected in the number of relatives affected by hearing impairment, of the genotype corresponding to the presence of both GSTM1 and GSTT1 enzymes and of cases with mitochondrial haplogroup L1.
  
  
  CONCLUSIONS
  The findings suggest effects of familial history of hearing loss, of GSTT1 and GSTM1 enzymes and of mitochondrial haplogroup L1 on the risk of NIHL. This study also described novel sequence variants of MTRNR1 and MTTS1 genes.
authors.affiliation: Centro de Estudos do Genoma Humano, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Brazil.
authors.forename: Ronaldo Serafim
authors.initials: RS
authors.lastname: Abreu-Silva
authors.forename: Daniel
authors.initials: D
authors.lastname: Rincon
authors.forename: Andréa Roseli Vançan Russo
authors.initials: AR
authors.lastname: Horimoto
authors.forename: Ary Papa
authors.initials: AP
authors.lastname: Sguillar
authors.forename: Luiz Artur Costa
authors.initials: LA
authors.lastname: Ricardo
authors.forename: Lilian
authors.initials: L
authors.lastname: Kimura
authors.forename: Ana Carla
authors.initials: AC
authors.lastname: Batissoco
authors.forename: Maria Teresa Balester De Mello
authors.initials: MT
authors.lastname: Auricchio
authors.forename: Paulo Alberto
authors.initials: PA
authors.lastname: Otto
authors.forename: Regina Célia
authors.initials: RC
authors.lastname: Mingroni-Netto
mesh_terms: D000328:Adult; D001483:Base Sequence; D001938:Brazil; D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006239:Haplotypes; D034381:Hearing Loss / Q000235:genetics; D006317:Hearing Loss, Noise-Induced / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
chemical_list: D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins; D005982:Glutathione Transferase; C000607042:GJB2 protein, human; C491020:GJB6 protein, human; C413545:glutathione S-transferase T1