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GM2 Gangliosidosis (Discovered in the Japanese Chin)

GM2 Gangliosidosis, is a disorder of progressive nervous system degeneration, with signs including incoordination of movements and tremors.

Key Signs

Ataxia, Intention tremors

Age of Onset

0 to 2 yrs

Juvenile onset


Autosomal Recessive

For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs 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 puppies if bred.

Likelihood of the Condition

High likelihood

At risk dogs are highly likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a dog with GM2 Gangliosidosis

Partner with your veterinarian to make a plan regarding your dog’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.

For Veterinarians

Here’s what a vet needs to know about GM2 Gangliosidosis

First signs of GM2 gangliosidosis are usually observed at one year of age. Characteristic signs include ataxia (uncoordinated movements), intention tremors of the head, vision impairment, altered mental status, and feeding difficulties. GM2 gangliosidosis is a progressive condition, so affected dogs will have increasing difficultly with everyday tasks such as walking and going up stairs, and may need assistance. Affected dogs are usually euthanized on welfare grounds by two years of age.

Upon initial observation of clinical signs, affected dogs should be closely monitored to assess welfare, and devise a supportive care treatment plan. As clinically signs are progressive, affected dogs are usually euthanized on welfare grounds by 2 years of age.

For Breeders

Planning to breed a dog with this genetic variant?

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. A carrier dog with one copy of the GM2 Gangliosidosis mutation can be safely bred with a clear dog with no copies of the GM2 Gangliosidosis mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the GM2 Gangliosidosis mutation. Puppies 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 puppies. Please note: It is possible that disease signs similar to the ones caused by the GM2 Gangliosidosis mutation could develop due to a different genetic or clinical cause.

Technical Details

Variant G>A
Chromosome 30
Coordinate 35,841,247

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Sanders, D. N., Zeng, R., Wenger, D. A., Johnson, G. S., Johnson, G. C., Decker, J. E., Katz, M. L., Platt, S. R., & O’Brien, D. P. (2013). GM2 gangliosidosis associated with a HEXA missense mutation in Japanese Chin dogs: A potential model for Tay Sachs disease. Molecular Genetics and Metabolism. View the article