Phenotype: Loss of cone function due to cone degeneration results in day-blindness and decreased visual acuity, with signs of the defect appearing between 8 and 12 weeks when retinal development is completed in dogs. Typically, affected dogs become increasingly photophobic as exposure to bright light is irritating and painful. Vision in low light conditions remains normal.
Mode of Inheritance: Autosomal recessive
Alleles: N = Normal, CD1 = CNGB3 cone degeneration variant (gene segment deletion), CD2 = CNGB3 cone degeneration variant (SNP nucleotide change)
Breeds appropriate for testing: Alaskan Malamute, Alaskan Sled Dog, Australian Shepherd, German Shorthaired Pointer, Miniature Australian Shepherd, Siberian Husky
Explanation of Results:
- Dogs with N/N genotype will not have these types of cone degeneration.
- Dogs with N/CD1 or N/CD2 genotype will not have these types of cone degeneration, but are carriers. They will transmit a cone degeneration variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% cone degeneration-affected puppies.
- Dogs with CD1/CD2, CD1/CD1, or CD2/CD2 genotype will have cone degeneration, an inherited disease that causes day-blindness.
Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)