NPC1L1 and age-related macular degeneration: We attempted to refine the findings for variants in the HMGCR and NPC1L1 gene regions using genetic risk scores based on multiple variants in each gene region that have previously been identified39; similar results were obtained for the associations of these scores with AMD risk (P = 0.042 for HMGCR, P = 0.082 for NPC1L1).