Maple Syrup Urine Disease (MSUD)
Maple syrup urine disease (MSUD) is an inherited disorder in which the body is unable to process certain protein building blocks properly. The condition gets its name from the distinctive sweet odor of affected infants' urine and is characterized in the neonatal period by poor feeding, vomiting, lethargy, and developmental delay. Maple syrup urine disease (MSUD) is inherited, which means it is passed down through families. It is caused by a defect in 1 of 3 genes. People with this condition cannot break down the amino acids leucine, isoleucine, and valine, leading to a toxic 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 absence of food). Some types of MSUD are mild or come and go. Even in the mildest form, repeated periods of physical stress can cause mental disability and a toxic build-up of leucine. If untreated, MSUD can lead to seizures, coma, and death.
Living with MSUD is difficult for patients and families. Diets must be very strictly controlled. Special metabolic foods are essential for survival, but are expensive and not always paid for by insurance. Individuals with MSUD remain at high risk for developing episodes of acute illness necessitating immediate medical intervention.
Although some MSUD patients are able to have a liver transplant, which allows them to live without fear of death from MSUD complications there is otherwise no known cure for MSUD. MSUD affects an estimated 1 in 185,000 infants worldwide, making it a rare disease. As with most rare diseases, research for MSUD lags far behind other diseases due to technological and funding limitations.
