INFORMATION ON MUCOPOLYSACCHARIDOSES

The Mucopolysaccharidoses are a number of metabolic disorders that follow a chronic and progressive course and involve many body systems. Mucopolysaccharides are long chains of sugar molecules that are essential for building the bones, cartilage, skin, tendons, and other tissues in the body. Mucopolysaccharidoses are a group of inherited 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.

SYNONYMS OF MUCOPOLYSACCHARIDOSES

Synonyms and Key Words

1. Lysosomal storage disease
2. Glycosaminoglycans
3. Hurler syndrome
4. Hurler-Scheie syndrome
5. Sanfilippo syndrome type A
6. Osteochondrodystrophy

CAUSES OF MUCOPOLYSACCHARIDOSES

The Mucopolysaccharidoses are a group of inherited metabolic disorders caused by a deficiency of specific lysosomal enzymes. The enzyme deficiency results in interference with cellular function because of excess accumulation within the cells of partially degraded glycosaminoglycans, which are also excreted to excess in the urine of affected patients. It is the accumulation of the glycosaminoglycans in the tissues and organs in the body that cause the wide array of symptoms characteristic of the mucopolysaccharidoses conditions. The accumulating material is stored in cellular structures called lysosomes, and these disorders are also known as lysosomal storage diseases.

SYMPTOMS OF MUCOPOLYSACCHARIDOSES

Glycosaminoglycans affect bone, skeletal structure, connective tissues, and organs. Neurological complications may include damage to neurons as well as pain and impaired motor function. Many individuals with an Mucopolysaccharidosis condition have problems with airway constriction. This constriction may be so serious as to create significant difficulties in administering general anesthesia. Physical symptoms generally include coarse or rough facial features short stature with disproportionately short trunk, dysphasia and other skeletal irregularities, thickened skin, enlarged organs such as liver or spleen, hernias, and excessive body hair growth. Short and often claw-like hands, progressive joint stiffness, and carpal tunnel syndrome can restrict hand mobility and function.

DIAGNOSIS OF MUCOPOLYSACCHARIDOSES

Scientists are working to identify the genes associated with the mucopolysaccharidoses syndromes and plan to test new therapies in animal models and in humans. Once a couple has had a child with an Mucopolysaccharidoses condition, prenatal diagnosis is available to them to help determine if a fetus is affected with the same Mucopolysaccharidoses as their other child. This can be accomplished through testing samples using procedures such as an amniocentesis or chorionic villus sampling. 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

TREATMENT OF MUCOPOLYSACCHARIDOSES

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. Biochemical tests are available that will identify healthy individuals who are carriers of the defective gene, allowing them to make informed reproductive decisions. Bone marrow transplantation has sometimes been found to help slow down the progression or reverse some of symptoms of the disorder in some children of such condition.