C3 and age-related macular degeneration: Age-related eye disease studies (AREDS) of AMD case-control subjects using 100,000 SNPs resulted in the identification of four chromosomal regions significantly associated with the disease, namely complement factor H (CFH) (1q32), the age-related maculopathy susceptibility 2(ARMS2)/Htra serine peptidase 1 (HTRA1) (10q26), complement component 2/complement factor B (C2/BF, 6p21), and complement component 3 (C3, 19p13).