We therefore presume that lipid and protein oxidative damage induced by MBG may be involved, at least in part, in the pathophysiology of the neurological dysfunction found in SBCADD-affected patients. Mutations in the HIBCH gene lead to 3-hydroxyisobutyryl-CoA hydrolase deficiency, an inborn error of valine catabolism that leads to the build up of a highly reactive intermediate, methacrylyl-CoA. Methacrylyl-CoA undergoes addition reactions with thiol compounds leading to the formation of S-2-carboxypropyl-cysteine (S2CP-cysteine) and S-2-carboxypropyl-cysteamine (S2CP-cysteamine).