Mucopolysaccharidoses
The mucopolysaccharidoses are a group of hereditary disorders affecting the connective tissue that result in a characteristic facial appearance and abnormalities of the bones, eyes, liver, and spleen, sometimes accompanied by mental retardation.
Mucopolysaccharides are essential parts of connective tissue. In the mucopolysaccharidoses, the body lacks enzymes needed to break down and store mucopolysaccharides. As a result, excess mucopolysaccharides enter the blood and are deposited in abnormal locations throughout the body.
During infancy and childhood, short stature, hairiness, and abnormal development become noticeable. The face may appear coarse. Some types of mucopolysaccharidoses cause mental retardation to develop over several years. In some types, vision or hearing may become impaired. The arteries or heart valves can be affected. Finger joints are often stiff.
A doctor usually bases the diagnosis on the symptoms and findings on a physical examination. The presence of a mucopolysaccharidosis in other family members also suggests the diagnosis. Urine tests may help but are sometimes inaccurate. X-rays may show characteristic bone abnormalities. Mucopolysaccharidoses can be diagnosed before birth using amniocentesis or chorionic villus sampling (see Section 22, Chapter 256).
Treatment and Prognosis
In one type of mucopolysaccharidosis, attempts at replacing the abnormal enzyme have had limited, temporary success. Bone marrow transplantation may help some people. However, death or disability often results, and this treatment remains controversial.
The prognosis depends on the type of mucopolysaccharidosis. A normal life span is possible. Some types, usually those that affect the heart, cause premature death.
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