GUANIDINOACETATE METHYLTRANSFERASE DEFICIENCY - NEW CLINICAL-FEATURES

Guanidinoacetate methyltransferase deficiency is a recently described inborn error of creatine biosynthesis that responds to treatment with oral creatine supplementation. The previously reported clinical featur es consist of developmental arrest and an extrapyramidal movement diso rder, We describe a patient who presented with epilepsy, global develo pmental delay, and a persistently low plasma creatinine level. The dia gnosis was established by measuring urinary guanidinoacetate and by de monstrating absence of the creatine/phosphocreatine peak in the patien t's basal ganglia in H-1 magnetic resonance spectroscopy. The clinical and biochemical abnormalities responded to creatine replacement, (C) 1997 by Elsevier Science Inc. All rights reserved.