What Is Maple Syrup Urine Disease?

By becky

Reviewed: Dr. Gromatzky

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2. What Causes Maple Syrup Urine Disease?

MSUD is a genetic disorder that is caused by a mutation in one or more of the four specific protein-producing genes that are responsible for breaking down certain amino acids. More specifically, individuals with MSUD are unable to properly break down the amino acids leucine, valine and isoleucine. These amino acids are found in many common foods that are high in protein, most notably dairy products. When the body is unable to properly break down these amino acids, they begin to accumulate. As the build-up progresses, the levels can become dangerous and in the worst cases, toxic. This is why it is so important to obtain a diagnosis and come up with a treatment plan, especially for infant patients.

In most cases, neither parent has maple syrup urine disease. Since the condition is recessive, both parents must either have or be carriers of the genetic mutation to pass it on to a child. Even when both parents are carriers, the children are more likely to also be carriers than to develop MSUD. For this reason, MSUD is considered a rare condition. A child of two carrier parents is actually just as likely to not be a carrier at all as he or she is to develop the condition.