X-Ray Repair Cross-Complementing Group 1 Genetic Polymorphisms and the Risk of Sudden Sensorineural Hearing Loss

OBJECTIVE: Sudden sensorineural hearing loss (SSNHL) is a condition with largely unknown etiology, though both vascular and genetic components have been implicated. The X-ray repair cross-complementing group 1 (XRCC1) gene, involved in DNA repair and oxidative stress response, has been linked to ischemic stroke and noise-induced hearing loss. This study aimed to investigate the association between XRCC1 single nucleotide polymorphisms (SNPs) and SSNHL risk in Taiwan. DESIGN: Prospective case-control study. SETTING: Tertiary academic medical center. MATERIALS AND METHODS: A total of 276 patients with SSNHL and 293 healthy controls were enrolled. Three XRCC1 SNPs (rs1799782, rs25489, and rs25487) were genotyped using TaqMan assays. All SNPs were tested for Hardy-Weinberg equilibrium. Associations with SSNHL risk were analyzed under dominant and recessive models using multivariate logistic regression. Clinical predictors of recovery were also evaluated. RESULTS: The TT genotype of XRCC1 rs1799782 was significantly associated with increased SSNHL risk compared with the CC genotype [adjusted odds ratio (aOR)=2.005; 95% CI=1.13-3.62; P =0.0164]. This association persisted under the recessive model (TT vs. CC+CT) (aOR=1.983; 95% CI=1.15-3.49; P =0.0134). No significant associations were observed for rs25489 and rs25487. High-tone (aOR=6.42; P = 0.0043) and flat-type (aOR=4.12; P =0.0071) audiogram patterns and longer treatment delay were linked to unfavorable clinical outcomes. XRCC1 genotypes were not predictive of treatment response. CONCLUSIONS: The TT genotype of XRCC1 rs1799782 is significantly associated with increased SSNHL susceptibility in the Taiwanese population.