ROC curve analysis indicated moderate diagnostic utility of 25(OH)D for distinguishing AMD patients from controls (AUC=0.714, 95% CI: 0.58-0.73, p<0.01), but limited ability to differentiate early vs. late-stage AMD Linear regression analysis revealed positive associations between 25(OH)D levels and apolipoprotein E (ApoE, β=0.157, p=0.04) and serum creatinine (β=0.18, p=0.02). The gene discussed is APOE; the disease is age-related macular degeneration.