BOTH THE clinical picture and the metabolic abnormality in maple urine disease pose special problems in its management. The rapid progression of symptoms (from feeding problems and apathy to the onset of central nervous system signs with periods of hypertonicity alternating with hypotonia, loss of Moro's reflex, difficulties with respiration to convulsions and death) makes prompt and proper treatment imperative. The nature of the defect, involving three essential amino acids, triples the problems of dietary management. In the seven years since treatment of the first case was initiated,1 our group at New York University has been able to develop a fairly well-defined schedule for initiating and continuing therapy.
The metabolic defect is the failure of oxidative decarboxylation of the keto-acid derivatives of the branched chain amino acids (Fig 1). This results in the accumulation of these compounds as well as of the branched chain amino acids (leucine, isoleucine, and