Editor,—Neurological dysfunction is a major clinical feature of children with maple syrup urine disease (MSUD). However, the mechanisms underlying the neuropathophysiology of the disorder are poorly known. There is some evidence associating the appearance of the neurological symptoms with increased plasma concentrations of leucine or its ketoacid, α ketoisocaproic acid or both.1 Impairment of brain energy production by inhibition of key mitochondrial enzymes by the acidic metabolites that accumulate in this disease has also been reported.2 …