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.
At risk dogs are highly likely to show signs of this disease in their lifetime.
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.
Mucopolysaccharidosis VI is a type of early onset lysosomal storage disease associated with progressive oculoskeletal signs. MPS VI is caused by a deficiency of arylsulfatase B (ARSB), which is an enzyme required for degradation of large sugar molecules, glycosaminoglycans, in lysosomes. ARSB enzyme deficiency causes glycosaminoglycans to build up within the cells, preventing normal cell function. This leads to stunted growth, systemic skeletal deformities and bilateral corneal cloudiness in affected dogs. The skeletal deformities may include facial dysmorphia, kyphosis (excessive curvature of the back), various limb abnormalities, and disproportionate dwarfism. Additional signs, such as a stiff, choppy hindlimb gait and joint crepitus, may be observed as the condition progresses. Affected dogs will typically begin showing clinical signs when young. And, due to the nature of the disorder, signs are progressive.
As there is no cure for this disorder, therapy is limited to symptomatic treatments and general supportive care. The average prognosis is considered poor for affected dogs and euthanasia is often considered at a young age for welfare reasons.
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 disorder is autosomal recessive, meaning two copies of the variant are needed for a dog to be at an elevated risk for being diagnosed with the condition. A carrier dog with one copy of the Mucopolysaccharidosis VI (Discovered in the Miniature Pinscher) variant can be safely bred with a clear dog with no copies of the Mucopolysaccharidosis VI (Discovered in the Miniature Pinscher) variant. About half of the puppies will have one copy (carriers) and half will have no copies of the variant. 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 disorder signs similar to the ones associated with this Mucopolysaccharidosis VI variant could develop due to a different genetic or clinical cause.
All coordinates reference CanFam3.1
Raj, K., Berman-Booty, L., Foureman, P., Giger, U. (2020). ARSB gene variants causing Mucopolysaccharidosis VI in Miniature Pinscher and Miniature Schnauzer dogs. Anim Genet, 51(6), 982-986. View the article