There is a disease called maple syrup urine disease, the disease is characterized by a sweet and distinctive odor in the urine that is similar to the maple syrup. The reason for MSUD is the deficiency in an enzyme that makes it hard to breakdown amino acids leucine, isoleucine, and valine. 1 in 180,000 infants are affected by MSUD in the United States, but it could be as high as 1 in 176 infants in certain inbred population like Mennonites in Pennsylvania. If MSUD is left untreated, it causes brain damage and other neurological issues and eventually leads to death.
The good thing is, individuals can still lead a normal life with the dietary restrictions and proper medical tests.