Mucopolysaccharidosis VII / MPS VII / Sly syndrome (GUSB-related) - Brazilian Terrier

What does this test assess?

This genetic test analyses the GUSB c.866C>T variant in the Brazilian Terrier. The condition is known as mucopolysaccharidosis type VII, MPS VII, Sly syndrome and beta-glucuronidase deficiency.

The GUSB gene encodes beta-glucuronidase, a lysosomal enzyme involved in breaking down glycosaminoglycans. When both gene copies carry the tested variant, these substances can no longer be degraded properly and may accumulate in cells and tissues.

What does this condition mean?

MPS VII is a severe lysosomal storage disorder. Affected dogs may develop developmental problems, skeletal and joint abnormalities, poor growth, neurological signs, eye changes and general weakness. Severity can differ between animals, but the genetically affected result is highly relevant for breeding decisions.

Inheritance and result

The trait is inherited as autosomal recessive. Carriers have one variant copy and can look healthy; dogs with two copies are genetically affected for this GUSB variant.

• CC means the dog does not carry the tested variant.
• CT means the dog is a carrier and can pass the variant to offspring.
• TT means the dog has two copies of the variant and is genetically affected for MPS VII caused by this variant.

Practical value of this test

This test gives breeders concrete control over a recessive disease variant that can remain hidden in a line. Especially in smaller breed populations or closely managed lines, it helps avoid risky pairings without unnecessarily losing valuable healthy dogs.

• The result clearly separates clear, carrier and genetically affected genotypes.
• Breeders can avoid carrier-to-carrier matings and prevent affected puppies.
• The test supports transparency for purchase, sale, mating decisions and international exchange of breeding animals.
• For relatives of a carrier or affected dog, DNA testing gives fast clarity about breeding risk.