Disease overview

Mucopolysaccharidoses (MPS) are a group of inherited metabolic diseases characterized by the improper degradation and accumulation of long chains of sugar molecules called glycosaminoglycans (GAG). This occurs as a result of the absence or malfunctioning of lysosomal enzymes, which have the important function of digesting and removing waste from the cells. The buildup of GAG in dogs causes abnormalities in the joints, bones, and other organs of the body. Mucopolysaccharidosis (MPS) VII, also known as Sly disease, is characterized by a deficiency of beta-glucuronidase, which is a lysosomal acid hydrolase.

Gene name

GUSB

Inheritance

Autosomal recessive

Signs and symptoms

Signs vary widely between different forms of Mucopolysaccharidoses (MPS). Dogs with MPS are usually diagnosed between two and five months of age, though progressive symptoms are typically apparent in the first month of life. The most common symptoms can include slow growth, dwarfism, large head, weakness in the hind legs and/or deformed legs, unusually broad chest, corneal clouding and/or ocular lesions, and liver and/or heart complications.

How is it diagnosed

A veterinarian will conduct a thorough exam, including a review of health history. Labwork and other diagnostics are needed to determine the causes of the wide range of symptoms associated with this disease. MPS may be suspected based on clinical signs, white blood cell granules, and a positive urine MPS spot test. Genetic testing can assist veterinarians with diagnosis and help breeders identify affected and carrier dogs.

Breeds at higher risk

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Citations

Ray J, Bouvet A, DeSanto C, Fyfe JC, Xu D, Wolfe JH, Aguirre GD, Patterson DF, Haskins ME, Henthorn PS. Cloning of the canine beta-glucuronidase cDNA, mutation identification in canine MPS VII, and retroviral vector-mediated correction of MPS VII cells. Genomics. 1998 Mar 1;48(2):248-53. doi: 10.1006/geno.1997.5189. PMID: 9521879.

Silverstein Dombrowski DC, Carmichael KP, Wang P, O'Malley TM, Haskins ME, Giger U. Mucopolysaccharidosis type VII in a German Shepherd Dog. J Am Vet Med Assoc. 2004 Feb 15;224(4):553-7, 532-3. doi: 10.2460/javma.2004.224.553. PMID: 14989549.

Hytönen MK, Arumilli M, Lappalainen AK, Kallio H, Snellman M, Sainio K, Lohi H. A novel GUSB mutation in Brazilian terriers with severe skeletal abnormalities defines the disease as mucopolysaccharidosis VII. PLoS One. 2012;7(7):e40281. doi: 10.1371/journal.pone.0040281. Epub 2012 Jul 5. PMID: 22815736; PMCID: PMC3395332.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.