title: Mental retardation and behavioral problems as presenting signs of a creatine synthesis defect.
abstract: Recently, 3 patients with a creatine synthesis defect have been described. They presented with developmental regression, extrapyramidal movement abnormalities, and intractable epilepsy, and they improved with treatment of creatine monohydrate. We report 2 unrelated boys with a creatine synthesis defect and nonspecific presenting signs of psychomotor retardation, behavioral problems, and, in 1, mild epilepsy. Metabolic urine screening revealed elevations in all metabolites, expressed as millimoles per mole of creatinine, which suggests decreased creatinine excretion. This finding led to the correct diagnosis. We propose to include the assessment of the overall concentrations of amino acids and organic acids relative to creatinine in routine metabolic urine screening.
authors.affiliation: Department of Child Neurology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: M S
authors.initials: MS
authors.lastname: van der Knaap
authors.forename: N M
authors.initials: NM
authors.lastname: Verhoeven
authors.forename: P
authors.initials: P
authors.lastname: Maaswinkel-Mooij
authors.forename: P J
authors.initials: PJ
authors.lastname: Pouwels
authors.forename: W
authors.initials: W
authors.lastname: Onkenhout
authors.forename: E A
authors.initials: EA
authors.lastname: Peeters
authors.forename: S
authors.initials: S
authors.lastname: Stöckler-Ipsiroglu
authors.forename: C
authors.initials: C
authors.lastname: Jakobs
mesh_terms: D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001826:Body Fluids / Q000737:chemistry; D001928:Brain Diseases, Metabolic / Q000175:diagnosis / Q000188:drug therapy / Q000378:metabolism; D002675:Child, Preschool; D003401:Creatine / Q000008:administration & dosage / Q000096:biosynthesis* / Q000652:urine; D003937:Diagnosis, Differential; D004827:Epilepsy / Q000175:diagnosis / Q000378:metabolism; D005500:Follow-Up Studies; D005998:Glycine / Q000031:analogs & derivatives / Q000032:analysis; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; C004946:glycocyamine; D003401:Creatine; D005998:Glycine