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Articles » NINDS Mucopolysaccharidoses Information Page: NINDS

NINDS Mucopolysaccharidoses Information Page: NINDS

Article title: NINDS Mucopolysaccharidoses Information Page: NINDS

Main condition: Mucopolysaccharidosis

Conditions: Mucopolysaccharidosis, Mucopolysaccharidosis I, Mucopolysaccharidosis II, Mucopolysaccharidosis III, Mucopolysaccharidosis IV, Mucopolysaccharidosis VI, Mucopolysaccharidosis VII, Mucopolysaccharidosis V (type of Mucopolysaccharidoses)

What is Mucopolysaccharidoses?
Mucopolysaccharidoses consist of a group of inherited metabolic disorders caused by a deficiency of the specific lysosomal enzymes needed to break down mucopolysaccharides. Mucopolysaccharides are long chains of sugar molecules used to build connective tissues and organs in the body. When mutations occur in the genes for the enzymes involved in the normal turnover of mucopolysaccharides, excess amounts of them are stored in the body, causing progressive damage and, in most cases, eventual death. Because some of the excess mucopolysaccharides are excreted through the urine, diagnosis often can be made through clinical examination and urine tests. Prenatal diagnosis is also available. Eight clinical types and numerous subtypes of mucopolysaccharidoses have been identified. Although each type differs clinically, generally, people with mucopolysaccharidoses experience a period of normal development followed by a decline in physical and/or mental function. Some of the more common types include:

Mucopolysaccharidosis I(MPS I), which includes Hurler, Scheie, and Hurler/Scheie syndromes. Hurler syndrome-the most severe form of the mucopolysaccharidoses -occurs in infancy with symptoms such as clouding of the cornea and progressive physical and mental disability. Death usually occurs before age 10. Patients with Scheie syndrome experience milder symptoms and have normal intelligence, while those with Hurler/Scheie syndrome suffer from intermediate symptoms.

MPS II, also called Hunter syndrome, affects juveniles and includes a mild and a severe form. Signs of the severe form are joint stiffness, mental deterioration, dwarfing, and progressive deafness. Death usually occurs by age 15. Symptoms of the mild form include short stature, limitation of motion, and features such as an enlarged forehead, lips, and tongue and misaligned teeth. Life span may be normal.

Individuals with MPS III, or Sanfilippo syndrome, experience progressive dementia and mental deterioration in childhood. Death usually occurs in the late teens.

Symptoms of MPS IV, or Morquio syndrome, usually appear in infancy and may include severe dwarfing and corneal clouding. Intelligence is normal. Cardiac or respiratory disease may cause death in the third or fourth decade of life. MPS VI, or Maroteauz-Lamy syndrome, resembles Hurler syndrome. Onset is in infancy, however, intelligence is normal. Individuals may live into the second or third decade.

Individuals with MPS VII, Sly disease, experience corneal clouding, skeletal irregularities, and enlargement of the liver and spleen. Intellectual impairments vary for this type of MPS.

Is there any treatment?
There is no cure for the mucopolysaccharidoses. Treatment is symptomatic and supportive. In several individuals, bone marrow transplants have been attempted with varying degrees of success. Enzyme replacement trials are under investigation for MPS I and MPS II.

What is the prognosis?
The prognosis for individuals with mucopolysaccharidoses varies depending on the type.

What research is being done?
The NINDS supports and conducts research aimed at finding the cause(s) of the various types of the mucopolysaccharidoses, and ways to treat, cure, and, ultimately, prevent the disorders. Because the genes for several forms of the mucopolysaccharidoses have been found, scientists are hopeful that understanding the genetics of the disorders may lead to breakthroughs in treatment.


National MPS Society, Inc.
102 Aspen Drive
Downingtown, PA 19335
Tel: 610-942-0100
Fax: 610-942-7188

National Organization for Rare Disorders (NORD)
P.O. Box 8923
(100 Route 37)
New Fairfield, CT 06812-8923
Tel: 203-746-6518 800-999-NORD (6673)
Fax: 203-746-6481

National Tay-Sachs and Allied Diseases Association
2001 Beacon Street
Suite 204
Boston, MA 02135
Tel: 617-277-4463 800-90-NTSAD (906-8723)
Fax: 617-277-0134

This fact sheet is in the public domain. You may copy it.Provided by:
The National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892


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