CTRB1 and age-related macular degeneration: Eight AMD loci (category 3: “CFH”, “COL8A1”, “TNFRSF10A”, “CETP”, “CTRB2/CTRB1”, “C3”, “CNN2”, and “MMP9”) revealed gene expression regulation effects only in extraocular tissues while five of these harbor multiple genes which were assigned to different categories.