C3 and age-related macular degeneration: Subsequently, more than 52 genetic variants at 34 genomic loci were found to be associated with AMD, most of which are common variants.2 In addition, rare variants in CFH, complement factor I (CFI), complement 3 (C3), complement 9 (C9), tissue inhibitor of metalloproteinases (TIMP3), and solute carrier family 16 member 8 (SLC16A8) genes have been identified in AMD.2,3,4,5,6,7,8,9