Testing of dogs: PRA in German Spitz
Related tests
- Combination German Spitz PRA in German Spitz + PRA-prcd + VWD Type II
Progressive retinal atrophy (PRA) in German Spitz
Progressive retinal atrophy is a large group of inherited eye diseases that are the leading cause of blindness in various breeds of dogs. Individuals affected by PRA show a similar sequence of clinical abnormalities throughout the course of disease. Symptoms begin with night blindness followed by progressive loss of daytime vision and eventual blindness in all light conditions. Routine eye examinations reveal a progressive loss of photosensitive cells (retina) due to their degeneration or retinal atrophy, which gives the name to the disease.
In German Spitz, the disease is caused by mutation c.1598_1599insT in the GUCY2D gene, which encodes a membrane guanylate cyclase 2D specific for retinal cells.
The mode of inheritance of the mutation is autosomal recessive. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. In the case of a mating between two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease.
The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to prevent unintentional breeding of affected puppies.
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Reference:
Bortolini, M., Winkler, P.A., Moreno, J.C.D., Sato, M.T., Guareschi, B.L.V., Petersen-Jones, S.M., Montiani-Ferreira, F. : Preliminary characterization of a novel form of progressive retinal atrophy in the German Spitz dog associated with a frameshift mutation in GUCY2D. Vet Ophthalmol :, 2023. Pubmed reference: 36872573