Commonly called "Maple Syrup Urine Disease" due to the thick, dark brown, sweet smelling urine of the affected human, Keto Acid Decarboxylase Deficiency is a genetic disorder that leads to mental and physical retardation in the mild case, and, more commonly, infant death.

The smell of the urine is a result of the keto acid of isoleucine (alpha-keto-beta-methylvaleric acid).

In some cases, the hyperaminoacidemia can be curtailed with 10mg per day doses of thiamine hydrochloride.