Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
Progressive retinal atrophy, or PRA, is the leading inherited cause of blindness in purebred dogs, with forms of the disease identified in over 100 breeds. In cats, two forms have been characterized. There are currently no clinically available treatments for PRA. The objectives of this poster are to provide information about and bring awareness to these feline forms of PRA, and to introduce possible preventative breeding strategies using genetic testing. The first form of feline PRA is caused by a mutation in the CEP290 gene and is recessively inherited. This form was originally identified in the Abyssinian breed but has since been recognized in over forty breeds. The disease is characterized by slowly-progressing photoreceptor degeneration with gradually decreasing electroretinogram (ERG) amplitudes, and eventual blindness occurring at 3–5 years of age. The second form is dominantly inherited and is caused by a mutation in the CRX gene. This form has thus far only been recognized in the Abyssinian breed. It is characterized by photoreceptor degeneration that occurs within the first weeks of life and leads to blindness within a few months. Through genetic testing it is possible for breeders to minimize these diseases in their lines, reducing their prevalence. Using common laboratory techniques such as polymerase chain reaction (PCR) and restriction enzyme digestion, we have developed genetic tests for both mutations. While the CRX form is early-onset and dominant, and therefore possible for breeders to identify without such testing, a genetic test is necessary for breeders to identify CEP290 carrier animals, as well as young CEP290 affected animals not yet showing signs of disease. We therefore developed a CEP290 mutation assay capable of identifying normal, affected, and carrier animals. Using the results from tests such as these, breeders can make informed breeding decisions allowing them to breed away from these mutations. In conclusion, PRA is a devastating disease that affects both cats and dogs and currently has no treatment. It is therefore essential that we help breeders decrease the prevalence of these diseases in their lines.