>babies usually will die within two weeks of birth or will become severely >retarded if not put on special diet. Maple Syrup Urine Disease (MSUD) is an inborn error of metabolism, which happens to cause the urine to smell like maple syrup. A special diet mitigates the damage caused by a build-up of by-products and excess amino acids in the blood, which exist because the normal metabolic pathways are blocked or inhibited. Like PKU (phenylketonuria), it involves defective amino acid metabolism. The outlook is poor. Arly in Northern Utah [log in to unmask] MS, CLE, IBCLC