CFHR4 and age-related macular degeneration: A common deletion spanning CFHR3 and CFHR1 (CNP147, 86.3 kb) and a rare deletion spanning CFHR1 and CFHR4 (CNP148, 122 kb) are both associated with a protective effect for AMD.22, 23, 24, 25, 26, 27, 28, 29 Additionally, systemic FHR-4 concentrations have been recently found to be elevated in individuals with AMD and to be associated with AMD genetic variants.30