Evaluation of Melasma Severity through Serum 8-Hydroxy-2′-Deoxyguanosine Biomarker and MC1R Gene Polymorphisms (rs1805006, rs772551710): A Case–Control Study in Adult Women: A Case-Control Study of Women in Baghdad

Melasma is a chronic hyperpigmentation condition caused by ultraviolet (UV) exposure, light skin pigmentation, and variations in the melanocortin 1 receptor (MC1R) gene. Clinically, it manifests in mandibular, malar, and centrofacial patterns. The study aims to clarify whether elevated levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG) as a biomarker correlate with increased melasma severity and if gene polymorphism (rs1805006 and rs772551710) variations in the MC1R gene influence this relationship. In a case-control study, 120 women from 20 - 50 years 60 took part, melasma and 60 of who had been age-matched healthy controls. Clinical diagnosis was established using Wood's light examination. Tetra-ARMS PCR was used to determine the MC1R genotypes, and ELISA had been utilized to measure levels of 8-OHdG of the serum. Of statistical analyses were one-way ANOVA, chi-square tests, independent t-tests, odds ratios (OR), and confidence intervals (CI). The Results rs772551710 II genotype (OR=3.28, p=0.002) and rs1805006 CA genotype (OR=4.67, p=0.0004) were significantly associated with melasma. Serum 8-OHdG conc. was markedly increased in patients (3.80 ± 0.22 ng/mL) compared with controls (0.603 ± 0.03 ng/mL, p<0.0001) and showed a strong positive correlation with Melasma Area and Severity Index (MASI) scores (r=0.929, p<0.0001). The optimal diagnostic cut-off for 8-OHdG was 1.59 ng/mL (96.7% sensitivity, 100% specificity; AUC=99.9%). Conclusions Both MC1R polymorphisms (rs1805006 and rs772551710) and elevated serum 8-OHdG are strongly associated with melasma severity. The 8-OHdG biomarker demonstrates high diagnostic accuracy and may be integrated into clinical assessment protocols.