title: N-acetyltransferase 2 gene polymorphism and presbycusis.
abstract: OBJECTIVE
  The enzyme of N-acetyltransferase (NAT) is involved in the metabolism and detoxification of cytotoxic and carcinogenic compounds as well as reactive oxygen species (ROS). The excessive amount of ROS generation occurs in the ageing inner ear. The exact etiopathogenesis of presbycusis is not known, but it is generally accepted that it is the result of series of insults, such as physiologic age-related degeneration, noise exposure, medical disorders and their treatment, as well as hereditary susceptibility. The effect of aging shows a wide interindividual range; we aimed to investigate whether profiles of NAT2 genotypes may be associated with the risk of presbycusis.
  
  
  METHODS
  Hospital-based, case-control study.
  
  
  METHODS
  We examined 68 adults with presbycusis and 98 healthy controls. DNA was extracted from whole blood, and the polymorphisms of NAT2*5A, NAT2*6A, NAT2*7A/B, and NAT2*14A were determined using a real-time polymerase chain reaction and fluorescence resonance energy transfer with a Light-Cycler Instrument. Associations between specific genotypes and the development of presbycusis were examined by use of logistic regression analyses to calculate odds ratios and 95% confidence intervals.
  
  
  RESULTS
  Gene polymorphisms at NAT2*5A, NAT2*7A/B, and NAT2*14A in subjects with presbycusis were not significantly different from in the controls (P > .05). However, in NAT2*6A, the risk of presbycusis was 15.2-fold more in individuals with mutant allele than subjects with wild genotype (P = .013). Individuals with NAT2*6A heterozygote allele had a 0.34-fold less risk in the development of presbycusis than subjects with mutant allele (P = .032)
  
  
  CONCLUSIONS
  We demonstrated a significant association between the NAT2*6A polymorphism and age-related hearing loss in this population. However, the sample size was relatively small, and further studies need to investigate the exact role of NAT2 gene polymorphism in the etiopathogenesis of the presbycusis.
authors.affiliation: Departments of Otorhinolaryngology, Faculty of Medicine, Mersin University, Mersin, Turkey. munal@mersin.edu.tr
authors.forename: Murat
authors.initials: M
authors.lastname: Unal
authors.forename: Lülüfer
authors.initials: L
authors.lastname: Tamer
authors.forename: Zeynep Nil
authors.initials: ZN
authors.lastname: Doğruer
authors.forename: Hatice
authors.initials: H
authors.lastname: Yildirim
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Vayisoğlu
authors.forename: Handan
authors.initials: H
authors.lastname: Camdeviren
mesh_terms: D000483:Alleles; D001191:Arylamine N-Acetyltransferase / Q000235:genetics* / Q000378:metabolism; D016022:Case-Control Studies; D004247:DNA / Q000235:genetics*; D005260:Female; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011304:Presbycusis / Q000201:enzymology / Q000235:genetics*; D011446:Prospective Studies
chemical_list: D005819:Genetic Markers; D004247:DNA; D001191:Arylamine N-Acetyltransferase; C478900:NAT2 protein, human