Progressive retinal atrophy - cord-1

Details about the disease

gPRA is a disease of the retina. This tissue, located inside the back of the eye, contains specialised cells called photoreceptors that absorb the light focused on them by the eye’s lens. They convert this light into electrical nerve signals which are then interpreted by the brain as vision. These photoreceptors are divided into two groups; the cones which aid bright light and colour vision, and the rods which facilitate low light or night vision. The cord-1 mutation causes both cone and rod deterioration, which results in initial night blindness, but usually progressing to total blindness in affected dogs.

Clinical Signs

The effects of this mutation were initially believed to result in an early onset form of PRA, typically with an age of onset around two years of age, but more recent results show that some dogs with two copies of this mutation are not diagnosed until much later in life, sometimes as late as 10 years of age.

How it is inherited

The disease is described as an autosomal recessive condition. This means that a dog must inherit two copies of an abnormal gene (one from its mother and one from its father) before its health is affected. A dog that inherits only one copy of the abnormal gene (from its mother or its father) will have no signs of the disease, but will be a carrier and may pass the gene on to any offspring.


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