The mucopolysaccharidoses are a group of inherited metabolic diseases in which a defective or missing enzyme causes large amounts of complex sugar molecules to accumulate in harmful amounts in the body's cells and tissues. This accumulation causes permanent, progressive cellular damage that affects appearance, physical abilities, organ and system functioning, and, in most cases, mental development. Depending on the type of mucopolysaccharidosis, affected individuals may have normal intellect or may be profoundly impaired, may experience developmental delay, or have severe behavioral problems. Physical symptoms generally include coarse or rough facial features, thick lips, an enlarged mouth and tongue, short stature with a disproportionately short trunk (dwarfism), abnormal bone size or shape (and other skeletal irregularities), thickened skin, enlarged organs such as the liver or spleen, hernias, and excessive body hair growth.
Currently there is no cure for these disease syndromes. Medical care is directed at treating systemic conditions and improving the person's quality of life. Physical therapy and daily exercise may delay joint problems and improve the ability to move. Surgery to remove tonsils and adenoids may improve breathing among affected individuals with obstructive airway disorders and sleep apnea. Surgery can also correct hernias, help drain excessive cerebrospinal fluid from the brain, and free nerves and nerve roots compressed by skeletal and other abnormalities. Corneal transplants may improve vision among patients with significant corneal clouding. Enzyme replacement therapy has proven useful in reducing non-neurological symptoms and pain. In 2006, the FDA approved the drug idursulfase (Elaprase) for the treatment of MPS II (Hunter syndrome). This is the first drug shown to have any benefit for one of the mucopolysaccharidoses.
The mucopolysaccharidoses syndromes share many clinical features but have varying degrees of severity. Most individuals with a mucopolysaccharidosis syndrome generally experience a period of normal development followed by a decline in physical and mental function. Longevity is dependent upon the particular syndrome. For example, children with a form of mucopolysaccharidosis called Hurler syndrome often die before age 10 from obstructive airway disease, respiratory infections, or cardiac complications. A child with the type known as Scheie syndrome can live into adulthood, while one with a mild case of the type known as Hunter syndrome may live into his or her 50s or beyond.
The National Institute of Neurological Disorders and Stroke (NINDS) conducts research in its laboratories at the National Institutes of Health (NIH) and also supports additional research through grants to major medical institutions across the country. Currently, scientists are working to identify the genes associated with the mucopolysaccharidoses syndromes and plan to test new therapies in animal models and in humans. Research funded by the Institute has shown that viral-delivered gene therapy in animal models of the mucopolysaccharidoses can stop the buildup of storage materials in brain cells and improve learning and memory. Researchers are planning additional studies, but it may be years before such treatment is available to humans.
National MPS Society, Inc.
PO Box 14686
Durham, NC 27709-4686
Tel: 877-MPS-1001 919-806-0101
National Organization for Rare Disorders (NORD)
55 Kenosia Avenue
Danbury, CT 06810
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
National Tay-Sachs and Allied Diseases Association
2001 Beacon Street
Boston, MA 02135
Tel: 800-90-NTSAD (906-8723)
Hunter's Hope Foundation
[A Leukodystrophy Resource]
P.O. Box 643
Orchard Park, NY 14127
Tel: 716-667-1200 877-984-HOPE (-4673)
Hide and Seek Foundation for Lysosomal Storage Disease Research
6475 East Pacific Coast Highway
Long Beach, CA 90803
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892
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Last Modified June 30, 2015