This progressive retinal atrophy is an inherited late-onset blindness condition seen in Abyssinian, Somali, and some Ocicat and other breeds. Affected cats have normal vision at birth that slowly degenerates to blindness.
Four mutations that produce long-haired coats in domestic cats have been identified in a single gene. Three of the mutations are fairly breed specific, while the fourth is present in all long-haired cat breeds and crossbreds.
Cats with colored 'points' have genetic mutations associated with temperature-sensitive pigment production. Pigment production is reduced in warmer areas of the body, leading to darker pigmentation in the cat's cooler extremities (paws, ears, etc.)
The agouti signaling protein interacts with the melanocortin 1 receptor to switch between black and red pigments, creating a banding pattern in individual hairs. Mutations in the agouti signaling protein gene (ASIP) prevent this switch from occurring, resulting in hairs of uniform color.