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Newborn Metabolic Screening Program

Maple Syrup Urine Disease (MSUD)

An Amino Acid Disorder:

What is it?
Maple Syrup Urine Disease (MSUD) is a disorder abnormally affecting the metabolism of amino acids. This disease is treated and managed very similar to the care of patients with PKU.

The disorder affects the way the body metabolizes certain components of protein. These components are the three branch-chain amino-acids leucine, isoleucine, and valine. These amino acids accumulate in the blood causing a toxic effect that interferes with brain function.

Inheritance and Frequency
The gene defect for MSUD is an autosomal recessive genetic trait and is unknowingly passed down from generation to generation. This faulty gene only emerges when two carriers have children together and pass it to their offspring. For each pregnancy of two such carriers, there is a 25% chance that the child will be born with the disease and a 50% chance the child will be a carrier for the gene defect.

MSUD affects approximately 1 in every 150,000 live births. MSUD was first described as a disease in 1954. It is believed to be in all ethnic groups worldwide.

Signs & Symptoms
This disease presents very dramatic signs in the newborn period such as poor feeding, lethargy, convulsions, and even death, occurring within the first few days of life.

Long Term Effects
Dietary restrictions must be maintained through the lifetime of an affected individual.

Treatment requires dietary restriction of branched-chain amino acids, a special medical formula (drink similar to milk) and intensive dietary monitoring.