For autosomal recessive disorders, cats with two copies of the variant are at risk of developing the condition. Cats with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their kittens if bred.
At risk cats are highly likely to show signs of this disease in their lifetime.
Partner with your veterinarian to make a plan regarding your cat’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.
GM2 Gangliosidoses are a group of neurodegenerative disorders caused by dysfunction in lysosomal storage. There are different types and causes of the disease. This form of the disease is caused by deficiency of the GM2 activator protein. The disease leads to accumulation of GM2 ganglioside within the lysosomes of neurons. Accumulation leads to cellular dysfunction, degeneration, and eventually to neuronal death. Clinical signs include progressive neurologic symptoms. The onset of clinical signs occurs at approximately twelve to fourteen months of age. The first clinical signs include ataxia, intention tremors, and an exaggerated startle reflex. The disease progresses to severe ambulatory difficulties with loss of coordination, difficulty eating, and blindness.
Upon initial observation of clinical signs, affected cats should be closely monitored to assess welfare and devise a supportive care treatment plan. As clinical signs are progressive, affected cats are usually euthanized on welfare grounds by two years of age.
There are many responsibilities to consider when breeding cats. Regardless of test results it is important that your cat is in good general health and that you are in a position to care for the kittens if new responsible owners are not found. For first time or novice breeders, advice can be found at most cat registry websites.
This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to be shown. A carrier cat with one copy of the GM2A mutation can be safely bred with a clear cat with no copies of the GM2A mutation. About half of the kittens will have one copy (carriers) and half will have no copies of the GM2A mutation. Kittens in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected kittens. Please note: It is possible that disease signs similar to the ones caused by the GM2A mutation could develop due to a different genetic or clinical cause.
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Martin, D. R., Cox, N. R., Morrison, N. E., Kennamer, D. M., Peck, S. L., Dodson, A. N., Gentry, A. S., Griffin, B., Rolsma, M. D., & Baker, H. J. (2005). Mutation of the GM2 activator protein in a feline model of GM2 gangliosidosis. Acta Neuropathologica, 110(5), 443–450. View the article