Stay Connected What is MPS 7? Mucopolysaccharidoses are a group of inherited metabolic disorders caused by the deficiency of any of the enzymes involved in the stepwise degradation of glycosaminoglycans (GAGs). Mucopolysaccharidosis type 7 (MPS 7) is an extremely rare form of MPS originally described by Dr. William Sly in 1973. Also referred to as Sly syndrome, MPS 7 is a lysosomal storage disorder characterized by a deficiency of the lysosomal enzyme, beta-glucuronidase, required for the degradation of the GAGs dermatan sulfate (DS) and heparan sulfate (HS). MPS 7 shares many features common to other MPS diseases, specifically MPS 1 and MPS 2. It is progressive in nature and affects many of the body's systems. There are no approved specific treatments for MPS 7.
The symptoms of MPS 7 include abnormal coarsened facies, hepatosplenomegaly (enlarged spleen and liver), pulmonary disease, cardiovascular complications, joint stiffness, short stature, and progressive skeletal dysplasia known as dysostosis multiplex. In more severe patients, there may be developmental delay as well.
The clinical course and disease progression of MPS 7 comprises a wide spectrum. The severe form of MPS 7 can uniquely present at birth with hydrops fetalis (severe generalized edema). This is a very severe neonatal condition in which the child retains an enormous amount of fluid throughout the body. Infants with hydrops fetalis rarely survive beyond a few weeks to a few months of age (Neufeld 2001). At the attenuated end of the spectrum, MPS 7 patients can present as adults with a less severe physical or skeletal disease.
Beyond the infant age, symptoms include increased urinary GAGs and dysostosis multiplex, but with variable onset and severity of other clinical features similar to several other MPS diseases. Other signs and symptoms include:
● hernias ● difficulty breathing as a result of airway obstruction and restriction leading to sleep apnea and frequent nasopharyngeal and respiratory infections including pneumonia ● heart disease (some degree of murmur or valvular leakage) ● hearing loss ● cataracts ● corneal clouding
Signs and symptoms may vary with each person with a broad range of severity.
National MPS Society The National MPS, Durham, NC, advocates for families affected by MPS and related diseases and promotes research initiatives.
International MPS Network The International MPS Network is the official body of the patient associations representing MPS and MPS societies at a European and global level.