PRA-RCD1 Irish Setter type (Progressive retinal atrophy)
PRA-RCD1 Irish Setter type is a genetic disorder that belongs in group of disorders known as progressive retinal atrophy. Progressive retinal atrophy (PRA) comprises autosomal recessively inherited diseases that lead to degeneration of retinal photoreceptor cells in dogs and other pets. In general, these diseases are characterized by disturbance of dark vision, visual field defects, and abnormalities in the electroretinogram, which can progress to blindness. The age of onset and rate of retinal degeneration varies between the different forms of the conditions. Some forms of PRA are common to multiple dog breeds, while others are recognized in just a single breed. Rod-cone dysplasias are group of recessively inherited diseases with early onset where photoreceptors are disturbed in their normal development and never manage to develop properly. The progression of rod-cone dystrophy is caused by sequential degeneration of rod and cone photoreceptors.
In PRA-RCD1 affected Irish setters retina and photoreceptor development appears normal until 13 days of age, but subsequent development of rod photoreceptor cells is arrested. Rod photoreceptor degeneration is evident by 1 month of age, nearly all of the rod photoreceptors have degenerated by 5 months, and cone photoreceptor degeneration is completed by about 1 year.
PRA-RCD1 cannot be treated, but it can be prevented with genetic testing prior to breeding. Breedings of untested dogs or dogs testing as carriers are at risk of producing PRA-RCD1 affected pups.
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