Answer:
MSUD stands for Maple Syrup Urine Disease. It is very rare, it occurs in about 1 of every 185,000 births worldwide. A child is born with MSUD when both parents are carriers of three specific gene mutations (changes) – one copy from each parent. These three specific amino acids are leucine, isoleucine and valine. Without the needed enzymes, the three amino acids build up and so do their toxic byproducts that are known as ketoacids.
MSUD occurs more often in communities that have little genetic variation (such as the Mennonite and Amish community) These groups have a closure of people (like they marry with their closed relatives) who are carriers of the mutated gene.