The OptiGen prcd-PRATest

 The OptiGen prcd-PRA test is a DNA-based test thathelps you avoid one form of Progressive Retinal Atrophy (PRA). PRA refers to agroup of diseases that cause the retina of the eye to degenerate slowly overtime. The result is declining vision and eventual blindness. prcd stands for progressive rod-cone degeneration which is the type of PRAknown in several breeds.

PRA Disease

The genetic disorder, prcd-PRA , causes cells in the retinaat the back of the eye to degenerate and die, even though the cells seemto  develop normally early in life. The rod cells operate in lowlight levels and are the first to lose normal function. Night blindnessresults. Then the cone cells gradually lose their normal function in fulllight situations. Most affected dogs will eventually be blind. Typically, theclinical disease is recognized first in early adolescence or early adulthood.Since age at onset of disease varies among breeds, you should read specificinformation for your dog. Diagnosis of retinal disease can be difficult.Conditions that seem to be prcd-PRA might instead be another disease andmight not be inherited. OptiGen’s genetic test assists in making thediagnosis. It is important to remember that not all retinal disease is PRAand not all PRA is the prcd form of PRA. Annual eye exams by aveterinary ophthalmologist will build a history of eye health that will help todiagnose disease.

Unfortunately, at this time there is no treatment or cure for PRA.

Inheritance

Prcd-PRA is inherited as a recessive trait. Thismeans a disease gene must be inherited from each parent in order to causedisease in an offspring. Parents were either carrier or affected. Acarrier has one disease gene and one normal gene, and is termed heterozygousfor the disease. A normal dog has no disease gene and is termed homozygousnormal, both copies of the gene are the same. And a dog with two disease genes istermed homozygous affected, both copies of the gene are abnormal.

It has been proven that all breeds being tested for prcd-PRAhave the same disease caused by the same mutated gene. This is so, even thoughthe disease might develop at different ages or with differing severity from onebreed to another.

Although prcd-PRA is inherited, it can be avoided in futuregenerations by testing dogs before breeding. Identification of dogs that do notcarry disease genes is the key. These clear dogs can be bred to any mate, even to a prcd-affected dog which may be a desirable breeding prospectfor other reasons. The chance of producing affected pups from such breedingsdepends on the certainty of test results. Again, you will find thespecific information on certainty of test results for your dog by linking tobreed specific information.

 The Genetic Test

The OptiGen prcd test is done on a small sample of blood from thedog. The test analyzes the specific DNA mutation causing prcd-PRA. The OptiGentest detects the mutant, abnormal gene copy and the normal gene copy. Theresult of the test is a genotype and allows separation of dogs into threegroups: Normal/Clear homozygous normal, Carrier heterozygous and Affectedhomozygous mutant.