Mucopolysaccharides are long chains of sugar molecules that are found throughout the body, often in mucus and in fluid around the joints. They are more commonly called glycosaminoglycans.

When the body cannot break down mucopolysaccharides, a condition called mucopolysaccharidoses (MPS) occurs. MPS refers to a group of inherited disorders of metabolism. People with MPS do not have any, or enough, of a substance (enzyme) needed to break down the sugar molecule chains.

Forms of MPS include:

• Hunter syndrome
• Hurler syndrome
• Sanfilippo syndrome
• Scheie syndrome
• Morquio syndrome

The conditions cause mucopolysaccharides to build up in body tissues. This can damage organs, including the heart. Symptoms can range from mild to severe and may include:

• Abnormal facial features
• Bone, cartilage, and connective tissue deformities
• Mental retardation

National Institute of Neurological Disorders and Stroke. Mucolipidoses Fact Sheet. Office of Communications and Public Liaison. Bethesda, MD; Publication No. 03-5115. February 13, 2007.