The search of a genetic basis for noise-induced hearing loss (NIHL).
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.
Abreu-Silva
Ronaldo Serafim
RS
Centro de Estudos do Genoma Humano, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Brazil.
Rincon
Daniel
D
Horimoto
Andréa Roseli Vançan Russo
AR
Sguillar
Ary Papa
AP
Ricardo
Luiz Artur Costa
LA
Kimura
Lilian
L
Batissoco
Ana Carla
AC
Auricchio
Maria Teresa Balester De Mello
MT
Otto
Paulo Alberto
PA
Mingroni-Netto
Regina Célia
RC
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
D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins; D005982:Glutathione Transferase; C000607042:GJB2 protein, human; C491020:GJB6 protein, human; C413545:glutathione S-transferase T1