Mucopolysaccharidosis VII (Brazilian Terrier Type)

General Information: Mucopolysaccharidosis VII (MPS VII) (Brazilian Terrier Type) is a genetic lysosomal storage disorder that severely impacts dogs, causing an accumulation of glycosaminoglycans (GAGs) due to insufficient activity of the enzyme beta-glucuronidase. GAGs are crucial components of connective tissue, and their buildup in cells results in abnormal growth and function of various organ systems. Affected dogs typically show symptoms between 1 to 4 weeks of age, primarily exhibiting bone and joint disease. These symptoms include disproportionately large heads with short muzzles, broad faces, and domed skulls, along with joint laxity and deformed, crooked legs, leading to an inability to walk. Affected puppies are smaller than their littermates, fail to thrive, and often die within the first 5 weeks of life either naturally or through euthanasia due to poor quality of life.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog Unlikely Affected

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing for Mucopolysaccharidosis VII (MPS VII) (Brazilian Terrier Type) involves screening for mutations in the GUSB gene to determine carrier status. This disorder is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene, one from each parent, to develop the disease. Carriers of the gene mutation do not typically exhibit symptoms but can pass the mutation to their offspring. When two carriers are bred, each puppy has a 25% chance of being affected and a 50% chance of being a carrier. To prevent producing affected puppies and eliminate the mutation from breeding lines, it is crucial to avoid breeding two carriers. Dogs that are not carriers of the mutation do not pose a risk of producing affected puppies, making genetic testing an essential tool in responsible breeding practices.