Mucopolysaccharidosis (MPS) is a genetic lysosomal storage disease that can cause various problems including stunted growth and bone deformities. There are a few different variants of this disease that have been identified in different breeds. For many breeds there are DNA tests available to identify if a breeding dog is carrying the condition.
Mode of Inheritance: autosomal recessive
Mucopolysaccharidosis VII (MPS VII) is a lysosomal storage disease characterized by accumulation of glycosaminoglycans (amino sugars) within cells. Glycosaminoglycans are found in cells involved with development of bone, cartilage, tendons, corneas, skin and connective tissue, and in fluid that lubricates joints. Under normal conditions of cell metabolism, these amino sugars are broken down into simpler sugars by the beta-glucuronidase enzyme encoded by the gene β- glucuronidase (GUSB). Mutations in the GUSB gene disrupt production or activity of this enzyme leading to an accumulation of amino sugars that causes permanent cell damage.
MPS VII disease has an early onset and is progressive. By one month of age, affected pups typically show shortened broad faces, low-set ears, and broad chests relative to unaffected littermates. By two months of age, corneal clouding is observed, and differential development is apparent with affected dogs being roughly half the size of unaffected siblings. As the disease progresses, standing becomes difficult and joints become swollen and are easily dislocated. Additional clinical signs include cardiac abnormalities, tracheal narrowing, and glycosaminoglycans in the urine.
