title: Guanidinoacetate methyltransferase deficiency: new clinical features.
abstract: Guanidinoacetate methyltransferase deficiency is a recently described inborn error of creatine biosynthesis that responds to treatment with oral creatine supplementation. The previously reported clinical features consist of developmental arrest and an extrapyramidal movement disorder. We describe a patient who presented with epilepsy, global developmental delay, and a persistently low plasma creatinine level. The diagnosis was established by measuring urinary guanidinoacetate and by demonstrating absence of the creatine/phosphocreatine peak in the patient's basal ganglia in 1H magnetic resonance spectroscopy. The clinical and biochemical abnormalities responded to creatine replacement.
authors.affiliation: Neurosciences Unit; Institute of Child Health (UCL) and Great Ormond Street Hospital for Children NHS Trust; London, England.
authors.forename: V
authors.initials: V
authors.lastname: Ganesan
authors.forename: A
authors.initials: A
authors.lastname: Johnson
authors.forename: A
authors.initials: A
authors.lastname: Connelly
authors.forename: S
authors.initials: S
authors.lastname: Eckhardt
authors.forename: R A
authors.initials: RA
authors.lastname: Surtees
mesh_terms: D000592:Amino Acid Metabolism, Inborn Errors / Q000201:enzymology / Q000235:genetics* / Q000628:therapy; D001479:Basal Ganglia / Q000473:pathology; D002675:Child, Preschool; D003401:Creatine / Q000008:administration & dosage / Q000096:biosynthesis*; D005500:Follow-Up Studies; D050937:Guanidinoacetate N-Methyltransferase; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008780:Methyltransferases / Q000172:deficiency*; D009460:Neurologic Examination; D010725:Phosphocreatine / Q000378:metabolism
chemical_list: D010725:Phosphocreatine; D008780:Methyltransferases; D050937:Guanidinoacetate N-Methyltransferase; D003401:Creatine