N-acetyltransferase 2 gene polymorphism and presbycusis.

Area of Science:

• Genetics
• Otolaryngology
• Biochemistry

Background:

• N-acetyltransferase (NAT) enzymes are crucial for metabolizing toxins and reactive oxygen species (ROS).
• Excessive ROS generation is implicated in age-related inner ear changes.
• The precise causes of presbycusis (age-related hearing loss) are multifactorial, including genetics.

Purpose of the Study:

• To investigate the association between N-acetyltransferase 2 (NAT2) genotypes and the risk of developing presbycusis.
• To explore the role of specific NAT2 polymorphisms in the etiopathogenesis of age-related hearing loss.

Main Methods:

• A hospital-based case-control study involving 68 adults with presbycusis and 98 healthy controls.
• DNA analysis using real-time polymerase chain reaction and fluorescence resonance energy transfer to determine NAT2 polymorphisms (NAT2*5A, NAT2*6A, NAT2*7A/B, NAT2*14A).
• Logistic regression analysis was used to calculate odds ratios and confidence intervals for genotype-associated risks.

Main Results:

• No significant differences in NAT2*5A, NAT2*7A/B, and NAT2*14A polymorphisms were observed between presbycusis patients and controls.
• A significant 15.2-fold increased risk of presbycusis was associated with the NAT2*6A mutant allele compared to the wild genotype (P = .013).
• Individuals with the NAT2*6A heterozygote allele showed a reduced risk (0.34-fold) compared to those with the mutant allele (P = .032).

Conclusions:

• A significant association exists between the NAT2*6A polymorphism and age-related hearing loss (presbycusis) in the studied population.
• The NAT2*6A polymorphism may play a role in the etiopathogenesis of presbycusis.
• Further research with larger sample sizes is warranted to elucidate the exact role of NAT2 gene polymorphisms in presbycusis.