Article Text

Download PDFPDF
Guanidinoacetate methyltransferase (GAMT) deficiency: a rare but treatable epilepsy
  1. William M Stern1,2,
  2. Joel S Winston3,4,
  3. Elaine Murphy5,
  4. J Helen Cross6,
  5. Josemir W Sander1,2,7
  1. 1 Department of Clinical and Experimental Epilepsy, NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, London, UK
  2. 2 Epilepsy Society, London, UK
  3. 3 Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, UK
  4. 4 Department of Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
  5. 5 Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
  6. 6 Institute of Child Health, UCL, London, UK
  7. 7 Stichting Epilepsie Instellingen Nederland (SEIN), Netherlands, UK
  1. Correspondence to Dr William M Stern, Clinical and Experimental Epilepsy, Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK; williamstern{at}


Epilepsy commonly presents in childhood as part of a syndrome, and some such children may reach adult services without an underlying syndromic diagnosis. For adult neurologists taking over their care, it is often unclear how hard to search for an underlying diagnosis. The diagnostic yield may be small and such a diagnosis may not change management. Young adults with learning difficulties are also challenging to investigate, as they may not tolerate standard epilepsy tests.

We present such a case in which simple tests identified a unifying diagnosis. With the new diagnosis came a new treatment that had a significant impact on seizures and quality of life.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Contributors WMS, EM, JHC and JWS were involved in the clinical care of the patient. WMS wrote the manuscript, with all authors participating in subsequent revisions. EM contributed the metabolic pathways. JSW provided the electroencephalogram figure and caption.

  • Competing interests JWS has received speaker honoraria from GlaxoSmithKline, Eisai, UCB, Lundbeck and Teva and was a member of the advisory boards for UCB and Eisai. He receives research support from the Dr Marvin Weil Epilepsy Research Fund, the Epilepsy Society (UK), the Netherlands Epilepsy Fund, Eisai, GlaxoSmithKline and UCB. He serves on the editorial board of the Lancet Neurology and his current position is endowed by the Epilepsy Society (UK). EM has received unrestricted educational grant funding and travel support from Genzyme and Shire Pharmaceuticals and funding for clinical trial work from Vitaflo, Ultragenyx, Genzyme, Shire and BiomarinPharmaceuticals. JSW is supported by a Wellcome Trust Postdoctoral Training Fellowship for MB/PhD Graduates (095939) and the Wellcome Trust Centre for Neuroimaging is supported by core funding from the Wellcome Trust (091593). JHC has received (all paid to her department) research monies from Vitaflo and GW Pharma, honoraria for advisory boards from Nutricia, Shire, Takeda, Eisai and GSK, and honoraria for speaking by Nutricia, Eisai, UCB and Shire, outside the submitted work.

  • Provenance and peer review Not commissioned; externally peer reviewed. 

    This paper was reviewed by Richard Appleton, Liverpool, UK, and Owen Pickrell, Cardiff, UK.

Other content recommended for you