Phenotype: PRCD affects the photoreceptor cells in the eye involved in both night and day vision. The cells of the retina involved in low light vision, known as rods, are affected first, resulting in night blindness. Subsequently, the bright light photoreceptors known as cones, which are important for color vision, are also affected, resulting in daytime visual deficit. The age of onset and rate of progression vary among breeds, but retinal changes can be identified by screening performed by a veterinary ophthalmologist from adolescence to early adulthood. Most PRCD-affected dogs have noticeable visual impairment by 4 years of age, typically progressing to complete blindness.
Mode of Inheritance: Autosomal recessive
Alleles: N = Normal, PRCD = Progressive rod-cone degeneration
Breeds appropriate for testing: Many breeds including but not limited to: American Eskimo Dog, American Hairless Terrier, Australian Cattle Dog, Australian Cobberdog, Australian Shepherd, Black Russian Terrier, Barbet, Chesapeake Bay Retriever, Chinese Crested, Chihuahua, Cockapoo, American Cocker Spaniel, Coton de Tulear, English Cocker Spaniel, English Shepherd, Entlebucher Mountain Dog, Field Spaniel, Finnish Lapphund, German Spitz, Giant Schnauzer, Golden Retriever, Golden Doodle, Jack Russell Terrier, Japanese Chin, Lab/Golden Cross, Labradoodle, Australian Labradoodle, Labradoodle/Goldendoodle Cross, Labrador Retriever, Miniature American Shepherd, Norwegian Elkhound, Nova Scotia Duck Tolling Retriever, Pomeranian, Poodle (Standard, Medium, Miniature and Toy), Portuguese Water Dog, Puli, Silky Terrier, Schipperke, Spanish Water Dog, Standard Poodle, Swedish Jamthund, Swedish Lapphund, Tibetan Terrier, Xoloitzcuintle, Yorkshire Terrier
Explanation of Results:
- Dogs with N/N genotype will not have this PRCD form of progressive retinal atrophy and cannot transmit this variant to their offspring.
- Dogs with N/PRCD genotype are not expected to be affected by this PRCD form of progressive retinal atrophy, but are carriers. They may transmit this PRCD variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% PRCD-affected puppies.
- Dogs with PRCD/PRCD genotype are expected to develop this PRCD form of progressive retinal atrophy and will transmit this variant to all of their offspring.
Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)