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Maple syrup urine disease - Overview

Alternative Names

MSUD

Definition of Maple syrup urine disease:

Maple syrup urine disease (MSUD) is a metabolism disorder passed down through families in which the body cannot break down certain parts of proteins. Urine in persons with this condition can smell like maple syrup.

Causes, incidence, and risk factors:

Maple syrup urine disease (MSUD) is caused by a gene defect. Persons with this condition cannot break down the branched-chain amino acids leucine, isoleucine, and valine. This leads to a buildup of these chemicals in the blood.

In the most severe form, MSUD can damage the brain during times of physical stress (such as infection, fever, or not eating for a long time).

MSUD also occurs in an intermittent form and a mild form. Even in the mildest form, repeated periods of physical stress can cause mental retardation and high levels of leucine.

Reviewed last on: 4/15/2009
Chad Haldeman-Englert, MD, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

References

Wendel U, Ogier de Baulny H. Branched-chain organic acidurias/acidemias. In: Fernandes J, Saudubray J-m, van den Berghe G, Walter JH, eds. Inborn Metabolic Diseases: Diagnosis and Treatment. 4th ed. New York, NY: Springer; 2006:chap 19.

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