CCL2 and age-related macular degeneration: Furthermore, mice deficient in CX3CR1 age-dependently develop AMD-like lesions [16], and mice deficient in both CCL2 and CX3CR1 have an early onset of retinal degeneration [30], although recent studies suggest that pathologies in the CCL2/CX3CR1 double knockout (DKO) mice is related to the Crb1 rd8 mutation [31], [32].