Diseases of branched-chain amino acid catabolism

Mutations in the genes that encode enzymes responsible for the catabolism of the branched-chain amino acids leucine, isoleucine and valine give rise to a number of inborn errors of metabolism (IEMs). Although IEMs are individually rare, collectively they are relatively common with an estimated overall prevalence of ~1:800 live births. The frequency of particular IEMs is also highly variable across different populations, a result in part of founder effects in closed populations. For instance, although the overall frequency of Maple Syrup Urine disease is 1:185,000 live births, the frequency rises to 1:380 in some Old Order Mennonite communities.

Summary from Reactome (R-HSA-9865118), read 2026-09-23.