MedlinePlus Medical Encyclopedia: Sanfilippo syndrome

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Sanfilippo syndrome

Contents of this page:
Alternative names Definition Causes, incidence, and risk factors Symptoms Signs and tests Treatment	Support Groups Expectations (prognosis) Complications Calling your health care provider Prevention

Alternative names

Mucopolysaccharidosis type III (subtypes A - B - C - D); Heparan sulfate sulfatase deficiency (Type IIIA); N-acetylglucosaminidase deficiency (Type IIIB); Acetyl-CoA alpha-glucosaminide N-acetyltransferase deficiency (Type IIIC); N-acetylglucosamine-6-sulfate sulfatase deficiency (Type IIID)

Definition Return to top

Sanfilippo syndrome is one of the hereditary mucopolysaccharide storage diseases, which are characterized by the absence of one of several enzymes. Normally, these enzymes help rid the body of a substance found outside of our cells, called a mucopolysaccharide.

In Sanfilippo syndrome, large amounts of a mucopolysaccharide called heparan sulfate is excreted in the urine.

Causes, incidence, and risk factors Return to top

Sanfilippo syndrome is transmitted as an autosomal recessive trait. It is possibly the most common of the mucopolysaccharide storage diseases. In Sanfilippo syndrome, onset is relatively late, rather than during the first year of life.

As with most of the mucopolysaccharide storage diseases, affected individuals have coarse facial features, decreased mental development that progresses to severe mental retardation, stiff joints, gait disturbances, speech disturbances, and behavioral problems.

Unlike Hurler syndrome, in people with Sanfilippo syndrome, the cornea is clear, the condition is not as unrelenting, and survival times are longer, often into the 20s or later.

Symptoms Return to top

Family history of Sanfilippo syndrome
May have normal growth during first few years, but final height is below average
Delayed development followed by deteriorating mental status
Deterioration of gait
Coarse facial features
Full lips
Heavy eyebrows that meet in the middle of the face above the nose
Diarrhea
Stiff joints that may not extend fully

Signs and tests Return to top

Hepatomegaly (liver enlargement)
Spleen enlargement
Clear corneas
Echocardiogram may show thickened heart
Abnormal bone X-rays, such as thickened skull and oval vertebrae
Seizures, mental retardation
Activities of one of the enzymes listed in "Alternate Names" may be low in fibroblast skin cells
Urine may have increased heparan sulfate
Abnormal, pathological staining character of white blood cells called metachromasia

Treatment Return to top

There is no specific treatment for Sanfilippo syndrome. Specific complications may respond to conventional treatments as they arise.

Support Groups Return to top

National MPS Society, Inc., www.mpssociety.org

Expectations (prognosis) Return to top

Severe retardation is the most important of the clinical problems. IQs may be below 50. Severe cases lead to death before 20 years of age.

In a minority of cases, Sanfilippo is compatible with a normal lifespan. The affected person may develop retinal degeneration leading to blindness, or may have seizures.

Complications Return to top

Blindness
Seizures
Mental retardation
Progressive neurologic disease leading to becoming wheelchair bound
Inability to care for self

Calling your health care provider Return to top

Call your health care provider if your child does not seem to be growing or developing normally.

Call for an appointment with your health care provider if you plan to have children and you have a family history of Sanfilippo syndrome.

Prevention Return to top

Genetic counseling is recommended for prospective parents with a family history of Sanfilippo syndrome.

Update Date: 8/6/2003

Updated by: Douglas R. Stewart, M.D., Division of Medical Genetics, Hospital of the University of Pennsylvania, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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