MMUT and methylmalonic acidemia: In particular, the isolated methylmalonic acidemia (MMA; OMIM #251000) is due to deficiency of the methylmalonyl-CoA mutase (MUT) enzyme which, in association with its cofactor 5’-deoxyadenosylcobalamin [5], is involved in the catabolism of odd-chain fatty acids, cholesterol, valine, methionine, isoleucine and threonine.