DNA testing for gangliosidosis (GM1) in dogs

Gangliosidosis (GM1 variant) is an uncommon type of metabolic disorder than can present in dogs. Gangliosidosis is a type of storage disease that develops when the dog in question is lacking a certain brain enzyme, which is responsible for the natural breakdown of molecules and that results in a dangerous accumulation of molecules in the dog’s brain, which in turn has an acute impact on the normal functions of the nervous system.

Gangliosidosis GM1 in dogs cannot be prevented or cured – but there is a DNA testing protocol in place for dogs of breeds that are considered to be at elevated risk of inheriting the disorder. Within the UK, the dog breeds considered to have elevated risk factors for gangliosidosis GM1 are the Shiba Inu, Siberian husky, and the Portuguese water dog.

Owners of dogs of these breeds who are considering breeding from them are strongly advised to undertake health testing on their parent stock, and prospective puppy buyers of dogs of these breeds should ask breeders about their health testing protocols and results before committing to a purchase.

In this article we will look at DNA testing for gangliosidosis GM1 in dogs, examining how the condition is inherited, what the gangliosidosis DNA test involves, and how to get a dog tested to determine their status. Read on to learn more.

What is gangliosidosis GM1?

Dogs that are affected by gangliosidosis don’t have enough of an enzyme called beta-galactosidase in their brains, which means that they are unable to break down certain carbohydrates within the body’s cells. This causes the build-up of GM1 within the cells, mainly cells within the nervous system and brain.

This causes a range of serious symptoms that have a huge impact on the dog’s quality of life, including vision loss, poor balance and an inability to walk normally, as well as lethargy, muscle spasms, tremors of the head, and weight loss.

Gangliosidosis GM1 in dogs is a hereditary disorder, passed on from parent dogs to their offspring by means of autosomal recessive heredity. A dog born with the affected form of the condition will generally begin to develop the first symptoms of neurological disease early on in their lives, generally at around six months of age. The condition progresses over the course of weeks or months, and by the time affected dogs reach their first birthday, they will usually display acute symptoms. Sadly, gangliosidosis GM1 is usually fatal in dogs by around fifteen months of age.

How is gangliosidosis GM1 passed from dog to dog?

Gangliosidosis GM1 is a hereditary disorder, which means that the only way for a dog to develop the condition is to inherit a certain combination of genes from both sides of their parentage. Gangliosidosis GM1 is an autosomal recessive genetic disorder, which means that it takes a specific combination of genes to be inherited from both parent dogs before a puppy will in turn be affected.

When it comes to expressing any dog’s status for gangliosidosis GM1, dogs are described as either clear, carrier or affected.

Clear dogs are neither affected by the condition nor able to pass on a propensity for it to their own young, whilst carriers may pass on carrier or affected status to their offspring depending on the status of the other dog within the mating match.

Here is how to determine the status of a litter based on the status of its parents:

• Two clear dogs will have a clear litter.
• Two affected dogs will have an affected litter.
• Two carrier dogs will produce a litter of 50% carriers, 25% clear and 25% affected.
• A clear dog and a carrier will produce a litter of 50% carriers and 50% clear.
• A clear dog and an affected dog will produce a litter of carriers.
• An affected dog and a carrier will produce a litter of 50% affected and 50% carrier pups.

Health testing for gangliosidosis GM1

In order to determine the odds of any puppy inheriting gangliosidosis GM1, prospective parent dogs can have their status determined by means of a simple DNA test.

Breeders of Siberian huskies, Portuguese water dogs and Shiba Inus are advised to have their breeding stock tested (and that of any prospective mate) before making a final decision on a mating match.

If you are thinking about buying a puppy of one of these three breeds, asking the breeder you are considering about their health testing and the status of the parents of the litter can help you to ensure that you make the right choice on your purchase, and to avoid purchasing an unhealthy dog.

How to get your dog DNA tested for gangliosidosis GM1

If you wish to get your dog DNA tested for gangliosidosis GM1 – either because you intend to breed from them or if you have concerns about your dog’s origins and want to know their risks – you just need to talk to your vet.

Your vet can take a DNA sample from your dog and send it away to an approved laboratory, which will test the sample and return a result on your dog’s status.