Steroid Combination Therapy and Detoxification Enzyme Gene Polymorphisms in Sudden Sensorineural Hearing Loss Patients

Objective: The purpose of this study was to evaluate the relations among the combined therapy with steroid and the detoxification enzyme gene polymorphisms in patients with sudden sensorineural hearing loss (SSNHL). The pathogenetic mechanism of inner ear dysfunction could involve an increase in lipid peroxidation and a decrease in cellular antioxidant defense. Glutathione S-transferases (GSTs) and cytochrome P450 (CYP) belong to a system of detoxification and antioxidant enzymes that have been demonstrated in the inner ear. Study Design: A prospective study in patients with SSNHL. Patients and Methods: All 441 subjects were genotyped for GSTM1, GSTT1, and CYP1A1 polymorphisms. The polymorphisms were analyzed by polymerase chain reaction amplification, restriction enzyme digestion, and deoxyribonucleic acid fragment separation by electrophoresis. Results: No significant difference was observed between SSNHL patients and controls in 3 polymorphisms. However, the prevalence of the partial recovery group in patients with the CC genotype of CYP1A1 (22%) was higher than that in the complete recovery (7.4%) or no recovery group (12.5%) for the subjects classified according to modified Siegel's criteria but were not statistically significant. Conclusion: This is the first approach to analyze gene polymorphism and efficacy of clinical treatment of patients with SSNHL, although the observations do not confirm the effect of the GSTM1/T1 and CYP1A1 genotypes as a risk factor for SSNHL.