Mucopolysaccharidosis is a group of genetic disorders that affect the production of enzymes needed to break down mucopolysaccharides, also known as glycosaminoglycans. When these substances are not properly broken down, they build up in the body's organs and tissues.
This buildup can interfere with several body functions and cause symptoms such as an enlarged liver and spleen, bone and joint deformities, and vision problems. The symptoms are progressive and may vary depending on the type of mucopolysaccharidosis and the areas of the body most affected.
Mucopolysaccharidosis has no cure, but treatment can help slow disease progression, prevent complications, and improve quality of life. Treatment may include enzyme replacement therapy, bone marrow transplantation, physical therapy, medications, and care from different medical specialists.
Signs and symptoms
The main signs and symptoms of mucopolysaccharidosis include:
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Enlarged liver and spleen
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Bone deformities
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Joint problems and reduced mobility
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Short stature
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Respiratory infections
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Umbilical or inguinal hernia
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Respiratory and cardiovascular disorders
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Hearing and vision problems
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Changes affecting the central nervous system
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Macrocephaly
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Delayed motor development
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Limited jaw movement
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Large mouth and enlarged tongue
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Gingival hyperplasia
According to the National Institute of Neurological Disorders and Stroke, the symptoms of mucopolysaccharidosis are progressive and can vary widely depending on the specific type of the disorder.
If signs or symptoms suggest mucopolysaccharidosis, it is important to see a primary care provider or medical geneticist as soon as possible so that the condition can be evaluated and treatment can begin promptly.
Life expectancy may be reduced in some people with mucopolysaccharidosis because complications can affect the function of multiple organs and body systems.
Main types
Mucopolysaccharidosis can be divided into several types based on which enzyme is deficient in the body:
- Type I: Hurler syndrome, Hurler-Scheie syndrome, or Scheie syndrome, caused by a deficiency of the enzyme alpha-L-iduronidase
- Type II: Hunter syndrome, caused by a deficiency of the enzyme iduronate-2-sulfatase
- Type III: Sanfilippo syndrome, caused by deficiencies involving the enzymes heparan N-sulfatase, alpha-N-acetylglucosaminidase, and acetyl-CoA-related enzymes involved in the breakdown of heparan sulfate
- Type IV: Morquio syndrome, caused by a deficiency of the enzymes galactose-6-sulfatase or beta-galactosidase
- Type VI: Maroteaux-Lamy syndrome, caused by a deficiency of the enzyme arylsulfatase B
- Type VII: Sly syndrome, caused by a deficiency of the enzyme beta-glucuronidase
According to the National Institute of Neurological Disorders and Stroke, enzyme testing can identify the specific enzyme deficiency and help confirm the type of mucopolysaccharidosis. Genetic testing may also be used to identify the underlying mutation.
Main cause
Mucopolysaccharidosis is a rare inherited genetic disorder, which means it is passed from parents to children. It is caused by the body's inability to produce certain enzymes needed to break down mucopolysaccharides.
Mucopolysaccharides are long-chain sugars that are important for forming several body structures, including the skin, bones, cartilage, and tendons. These substances are normally broken down and replaced through the activity of specific enzymes.
In mucopolysaccharidosis, a genetic mutation interferes with the production of these enzymes and disrupts the normal breakdown process. As a result, glycosaminoglycans build up inside the body's cells, impairing their function and contributing to physical abnormalities and other health problems.
Treatment options
Treatment for mucopolysaccharidosis should be guided by a medical team experienced in inherited metabolic disorders and depends on the specific type and severity of the condition. Treatment should begin as early as possible, as this may help slow disease progression and reduce the risk of complications.
For certain types of mucopolysaccharidosis, treatment may include enzyme replacement therapy to replace the enzyme that is deficient in the body. This treatment can help reduce glycosaminoglycan buildup and improve some symptoms, although its effects vary depending on the type of mucopolysaccharidosis and the organs affected.
The doctor may also recommend treatments to manage specific symptoms. Depending on the person's needs and type of mucopolysaccharidosis, treatment may include hematopoietic stem cell transplantation, physical therapy, and follow-up care with an ophthalmologist, orthopedic specialist, neurologist, psychologist, speech-language pathologist, or dentist.