Sanfilippo syndrome

Alternative Names

MPS III

Definition of Sanfilippo syndrome

Sanfilippo syndrome is an inherited disease of metabolism that makes the body unable to properly break down long chains of sugar molecules called glycosaminoglycans (formerly called mucopolysaccharides).

Causes, incidence, and risk factors

Sanfilippo syndrome occurs when the substances (enzymes) needed to break down the heparan sulfate sugar chain are missing or are defective.

Symptoms

Unlike other forms of MPS, symptoms appear after the first year of life. A decline in learning ability typically occurs between ages 2 and 6. The child may have normal growth during the first few years, but final height is below average. Delayed development is followed by deteriorating mental status.

Signs and tests

A physical exam may show signs of liver and spleen swelling. An eye exam will show clear corneas, unlike the cloudy corneas seen in persons with Hurler syndrome (MPS I H). Neurological testing will reveal signs of seizures and mental retardation.

Treatment

There is no specific treatment available for Sanfilippo syndrome.

Expectations (prognosis)

The syndrome causes significant neurological symptoms, including severe retardation. IQs may be below 50. Most persons with Sanfilippo syndrome live into their teenage years. Some patients live longer, while others with severe forms die at an earlier age. Symptoms appear most severe in persons with type A Sanfilippo syndrome.

Review

Diana Chambers, MS, EdD, Certified Genetics Counselor (ABMG), Charter Member of the American Board of Genetic Counseling, University of Tennessee, Memphis, TN. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 5/11/2009

ADAM Medical Encyclopedia

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