Long-term follow-up and treatment in nine boys with X-linked creatine transporter defect

J Inherit Metab Dis. 2012 Jan;35(1):141-9. doi: 10.1007/s10545-011-9345-1. Epub 2011 May 10.


The creatine transporter (CRTR) defect is a recently discovered cause of X-linked intellectual disability for which treatment options have been explored. Creatine monotherapy has not proved effective, and the effect of treatment with L-arginine is still controversial. Nine boys between 8 months and 10 years old with molecularly confirmed CRTR defect were followed with repeated (1)H-MRS and neuropsychological assessments during 4-6 years of combination treatment with creatine monohydrate, L-arginine, and glycine. Treatment did not lead to a significant increase in cerebral creatine content as observed with H(1)-MRS. After an initial improvement in locomotor and personal-social IQ subscales, no lasting clinical improvement was recorded. Additionally, we noticed an age-related decline in IQ subscales in boys affected with the CRTR defect.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Transport Disorders, Inborn / genetics
  • Amino Acid Transport Disorders, Inborn / therapy*
  • Arginine / metabolism
  • Arginine / therapeutic use
  • Brain / pathology
  • Child
  • Child, Preschool
  • Chromosomes, Human, X*
  • Creatine / therapeutic use
  • Genes, X-Linked
  • Glycine / therapeutic use
  • Humans
  • Infant
  • Intelligence Tests
  • Magnetic Resonance Spectroscopy / methods
  • Male
  • Membrane Transport Proteins / genetics*
  • Neurons / metabolism


  • Membrane Transport Proteins
  • creatine transporter
  • Arginine
  • Creatine
  • Glycine