Cone Degeneration (CD)
Cone Degeneration (CD) is an autosomal recessive disease that occurs in the German Shorthaired Pointer and Alaskan Malamute and several other breeds. It is phenotypically similar to human achromatopsia, also an autosomal recessive disorder. Both the canine disease and its human counterpart are characterized by day-blindness and the absence of a retina.
CD disease causes degeneration of the retinal "cones" that respond primarily to bright daylight, resulting in what is referred to as "day blindness." CD was first observed in an in-bred strain of Alaskan Malamute dogs in 1960 and is inherited as an autosomal recessive trait (15). Cone-degenerate pups develop day-blindness and photophobia between 8 and 12 weeks of age, the age when retinal development is normally completed in dogs. Symptoms of CD are present only in bright light and the dog's vision is not affected in dim light.
Animal Genetics accepts buccal swab, blood, and dewclaw samples for testing. Sample collection kits are available and can be ordered at Canine Test Now.
Test Is Relevant to the Following Breeds:
- Alaskan Malamute
- German Shorthaired Pointer
Animal Genetics UK offers DNA testing for Cone Degeneration (CD). The genetic test verifies the presence of the recessive gene and presents results as one of the following:
|CD/CD||Affected||The dog carries two copies of the mutant gene and is homozygous for the CD mutation. The dog will display symptoms associated with the disorder and will always pass a copy of the mutation to its offspring.|
|CD/n||Carrier||Both the normal and mutant copies of the gene detected. Dog is a carrier for the CD mutation and can pass on a copy of the defective gene to its offspring 50% 0f the time.|
|n/n||Clear||Dog tested negative for the CD gene mutation and will not pass on the defective gene to its offspring.|