The cause of this condition is the loss of the retinal pigment epithelium's ability to effectively process the photoreceptor outer segment (POS) and subsequent accumulation of POS material in the RPE and loss of function. The loss of function of the RPE leads to photoreceptor degeneration.

Progressive retinal atrophy is genetic, so dogs inherit it from their parents. It’s usually caused by something called an autosomal recessive trait, and dogs with this trait receive defective gene copies from both parents, not just one. In some breeds, however, it’s more likely for dogs to inherit a defective gene copy from just one parent.

Causes Several different genetic variants can cause PRA, but all of them lead to the same outcome: cell degeneration in the retina, which is located in the back of the eye.

PRA is caused by wasting or degeneration of the light-sensitive rods and cones. Degeneration tends to be nonpainful, in contrast to inflammatory/degenerative conditions, such as arthritis, which are sore.