Maple Syrup Urine Disease may sound like something made up in a cartoon, but it is, in fact, a real disorder. As part of Maple Syrup Urine Disease, the body is unable to break down parts of proteins, which results in the urine smelling lie maple syrup. The disorder is inherited and caused by a defect in the genes. While some people suffer from Maple Syrup Urine Disease on a regular basis, others have flare-ups or just mild symptoms. Leucine, isoleucine, and valine are the three amino acids unable to be broken down by people with this condition, and the result is urine that many think have an odor that resembles maple syrup.