Sandhoff disease or gangliosidosis variant 0 (GM2) DNA testing for the Japanese Chin

The Japanese chin (also sometimes known as the Japanese spaniel) is a very small and finely boned dog that is grouped within the Kennel Club’s toy dog category, and these petite, refined and very elegant-looking little dogs are popular lapdogs that love nothing more than cuddling up on the sofa to relax with their favourite people.

Japanese chins are quite versatile, middle of the road dogs in terms of their core traits, with average intelligence, a tendency to be quite amenable to learning basic training commands, and not having overly onerous grooming requirements. They are also quite moderate in terms of their need for exercise, and whilst every single dog needs to be walked appropriately every day, this is not a breed that will run you ragged or tire you out just keeping up with them!

On the flipside, Japanese chins tend to enjoy a quiet, relaxed lifestyle and may find living with children challenging, and there is also quite a long list of hereditary health conditions that can be found across the breed population as a whole.

One such condition is called Sandhoff disease, which you might also hear referred to as gangliosidosis variant 0 or GM2. This hereditary health condition of the Japanese chin breed is a type of lysosomal storage disease, which affects the dog’s ability to process and break down certain enzymes.

Because Sandhoff disease is hereditary, a parent dog with the condition (or that is a carrier of the condition) may pass it on to their own young, depending on the status of the other dog involved in the mating match.

For this reason, Japanese chin owners who may be considering breeding from their dog are advised to get their dog DNA tested for the markers of the condition first, and to ensure that the other dog within the mating match is tested too.

In this article we will provide a short explanation of Sandhoff disease in the Japanese chin, outline how the disease is inherited, and explain what you need to do to get your dog DNA tested and find out their own status.

Read on to learn more about Sandhoff disease DNA testing for the Japanese chin.

What is Sandhoff disease or gangliosidosis variant 0 (GM2)?

When you hear your vet or another professional talk about Sandhoff disease, you might also hear it referred to as gangliosidosis variant 0 (GM2), and both of these terms refer to the same condition.

Sandhoff disease in Japanese chins is a progressive hereditary neurodegenerative disorder that is a type of lysosomal storage disease. Dogs with Sandhoff disease are unable to break down certain types of natural enzymes that are necessary in order to enable the normal degradation of the dog’s neuronal membrane.

Over time, this causes a progressive breakdown and widespread destruction of the dog’s central nervous system, which worsens over time.

The symptoms of Sandhoff disease in Japanese chins include poor balance or difficulty walking, tremors (particularly of the head) and vision loss.

Generally, dogs that inherit the condition begin to become symptomatic between the ages of around nine months and one year old, and once symptoms develop, the progression of Sandoff disease in Japanese chins is usually fast, resulting in death between the ages of around eighteen months and two years of age.

How is Sandhoff disease in the Japanese chin inherited?

Sandhoff disease or gangliosidosis variant 0 (GM2) is a hereditary health disorder that can only be passed from dog to dog by means of inheritance.

The mode of inheritance of Sandhoff disease in the Japanese chin is autosomal recessive, which means that whether or not any puppy will be affected by the condition depends on the status of both of their parents. A dog’s status for Sandhoff disease can be either clear, carrier or affected, and you can find out the status of any given dog with a DNA test that we will explain in more detail later on.

When you know the status of any two prospective parent dogs, you can work out the odds of their future pups inheriting it too. Here’s how the heredity of Sandhoff disease in the Japanese chin works:

• Two clear parent dogs will have a clear or unaffected litter.
• Two affected parent dogs will have a litter within which all of the puppies are also affected.
• Two carrier parent dogs will produce a litter within which each pup has a 50% chance of also being a carrier, a 25% chance of being clear, and a 25% chance of being affected.
• A clear parent and an affected parent will produce a litter of carriers.
• A clear parent and a carrier will produce a litter of 50% clear pups and 50% carriers.
• A carrier and an affected dog will produce a litter of 50% carriers and 50% affected.

DNA testing for Sandhoff disease in the Japanese chin dog breed

If you are considering breeding from your Japanese chin, it is very wise to have them DNA tested for Sandhoff disease first, to ensure that you don’t produce a litter that will be affected too. Both parent dogs must be tested before you can predict the status of their litter, and this is really easy to arrange with your own vet.

Book an appointment at your local clinic and ask your vet to take a DNA sample from your dog for Sandhoff disease testing, and this sample is then sent off to the appropriate laboratory that carries out the test itself.

The results for each dog are returned as either clear, carrier or affected, and being able to demonstrate to prospective puppy buyers that the parent dogs were health tested and produced a healthy litter can help to secure a successful sale to a responsible dog owner.