Sex-Specific Association Between XPC rs2228001 Polymorphism and Parkinson’s Disease Risk in a Mexican Population: A Case–Control Study Exploring Gene–Environment Interactions

Background/Objectives: Emerging evidence implicates impaired DNA repair mechanisms in the pathogenesis of Parkinson’s disease (PD), particularly in the context of oxidative stress and environmental exposures. This study investigated the association between five polymorphisms in nucleotide excision repair (NER) pathway genes and PD susceptibility in a northern Mexican mestizo population. Methods: We conducted a case–control study including 137 patients with clinically diagnosed PD and 137 age- and sex-matched controls. Genomic DNA was isolated from peripheral blood, and genotyping of ERCC1 (rs11615), ERCC2 (rs13181), XPA (rs1800975), XPC (rs2228001), and XPF (rs1799801) was performed using TaqMan real-time PCR assays. Associations between genotype frequencies and PD were evaluated using logistic regression models adjusted for age, sex, and pesticide exposure. Results: A significantly higher prevalence of pesticide exposure was observed in PD patients than in controls (OR 2.08, 95% CI 1.18–3.68; p = 0.01). The XPC rs2228001 C/C genotype was independently associated with increased PD risk in males (OR 3.25, 95% CI 1.07–9.85; p = 0.042), even after adjusting for uric acid, pesticide exposure, and cognitive status (MMSE score). No significant associations were found for other NER-related polymorphisms. Male PD patients also exhibited significantly lower serum uric acid levels than controls (p = 0.046), supporting a link between oxidative stress and disease vulnerability. Conclusions: Our findings suggest a sex-specific genetic contribution to PD susceptibility involving the XPC rs2228001 variant, particularly in the context of pesticide exposure. These results underscore the relevance of DNA repair pathways in PD pathogenesis and highlight the importance of integrated models incorporating genetic and environmental risk factors.