Angiotensin-Converting Enzyme (ACE) I/D and Alpha-Adducin (ADD1) G460W Gene Polymorphisms in Turkish Patients with Severe Chronic Tinnitus

OBJECTIVE: Tinnitus is described as a disturbing sound sensation in the absence of external stimulation. We aimed to investigate whether there is any relationship between severe chronic tinnitus and angiotensin-converting enzyme (ACE) I/D and alpha-adducin (ADD1) G460W gene polymorphisms. MATERIALS and METHODS: The patient group and control group consisted of 89 and 104 individuals, respectively. The evaluation of tinnitus was performed using the Strukturiertes Tinnitus-Interview (STI). The Tinnitus Handicap Inventory (THI) was used to evaluate the tinnitus severity. Polymerase chain reaction (PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques were used for genotyping. RESULTS: With regard to the ACE I/D polymorphism, there was no significant difference in genotype and allele frequencies between the patient group and control group. However, a statistically significant difference was found in genotype (p< 0.01) and allele frequencies (p= 0.021) of the ADD1 G460W gene polymorphism. Combined genotype analysis showed that the ACE II /ADD1 GW genotype was statistically significantly higher in the patient group than in the control group (X2: 7.15, p= 0.007). The odds ratio value of the GW genotype was 2.5 (95% CI= 1.4-4.7) (p< 0.01). CONCLUSION: Our results demonstrate an association between ADD1 G460W gene polymorphism and susceptibility to severe chronic tinnitus. It was found that the GW genotype increased the disease risk by 2.5-fold compared with other genotypes. This indicates that ADD1 G460W polymorphism could be an important factor in the pathophysiology of tinnitus.