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Mucopolysaccharidoses occur when the body lacks enzymes needed to break down and store complex sugar molecules.
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Typically, symptoms include short stature, hairiness, stiff finger joints, and coarseness of the face.
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The diagnosis is based on symptoms, a physical examination, and blood tests.
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Although a normal life span is possible, some types cause premature death.
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Treatment may include lifelong enzyme replacement therapy, and sometimes a bone marrow transplant.
There are different types of inherited disorders. In many hereditary metabolic disorders, both parents of the affected child carry a copy of the abnormal gene. Because usually two copies of the abnormal gene are necessary for the disorder to occur, usually neither parent has the disorder. Some hereditary metabolic disorders are X-linked, which means only one copy of the abnormal gene can cause the disorder in boys. (See also Overview of Hereditary Metabolic Disorders.)
Complex sugar molecules called mucopolysaccharides (glycosaminoglycans) are essential parts of many body tissues. In mucopolysaccharidoses, the body lacks enzymes needed to break down (metabolize) and store mucopolysaccharides. As a result, excess mucopolysaccharides enter the blood and are deposited in abnormal locations throughout the body.
Types of mucopolysaccharidosis
Symptoms
Different types of mucopolysaccharidosis have slightly different symptoms but, in general, during infancy and childhood, short stature, hairiness, and abnormal development become noticeable. The face may appear heavy with a large head, prominent forehead, short nose, and large lips and tongue. Some types of mucopolysaccharidoses cause intellectual disability that may worsen over the course of a person's life. In some types, vision or hearing may become impaired. The arteries or heart valves can be affected. Finger joints are often stiff.
Types of Mucopolysaccharidoses
Diagnosis
Before birth, mucopolysaccharidoses can be diagnosed by using the prenatal screening tests amniocentesis or chorionic villus sampling.
After birth, a doctor usually bases the diagnosis of mucopolysaccharidoses on the symptoms and 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 also are diagnosed by analyzing blood cells. Genetic testing, which is used to determine whether a couple is at increased risk of having a baby with a hereditary genetic disorder, is available.
Other tests are done depending on symptoms. For example, children who have heart problems may undergo the imaging test echocardiography, and children who have hearing problems may undergo audiometry.
Prognosis
Treatment
Lifelong enzyme replacement therapy is being used to treat some mucopolysaccharidoses and may prevent the disorders from getting worse and reverse some of the complications.
Bone marrow transplantation or stem cell transplantation may help some people. However, these procedures may result in death or disability, so these treatments remain somewhat controversial.
