Intermittent maple syrup urine disease in a 12-year-old boy: clinical aspects, diagnosis and treatment

A variant form of maple syrup urine disease (grade II) in a twelve year old boy is reported. The clinical picture was characterized by seizure-like episodes of confusion and intermittent ataxia. The diagnosis was made by showing an increased excretion of branched-chain alpha-hydroxy acids as well as evaluated plasma concentrations of the branched-chain aminoacids and alpha-ketoacids. There was a decrease of leucine degradation in cultured fibroblasts to 5 to 6% of normal. The treatment with thiamine-hydrochlorid remained without any clinical or biochemical effect in our patient. Further neurologic symptoms during acute episodes of vomiting could be avoided by dietary protein restriction and early parenteral glucose supplementation.