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Wednesday, November 27, 2013

Perhaps the most commonly reported “indication” for the ketogenic diet mentioned in health literature is GLUT-1 deficiency syndrome. In fact, most experts believe the ketogenic diet is the best treatment for this condition, in which the brain cannot adequately use glucose as a fuel. Historically, most children with GLUT1 will have difficult-to-control seizures, abnormal development, and sometimes a movement disorder with clumsiness and poor balance. In the past, the only way to diagnose GLUT1 was through a lumbar puncture (spinal tap), so it was not commonly found. Now, there is a blood genetic test (SLC2A1, found on chromosome 1), so it’s easier to diagnose. In recent years, it has been surprising to discover that children with early-onset (< 3 years of age at presentation) absence epilepsy have been diagnosed with GLUT1.

Just as the diagnosis of GLUT1 has changed over the years, so has the way we have thought about treatment. Years ago, the family of a child newly-diagnosed with GLUT1 traditionally was told that the ketogenic diet was critical. The diet uses a high ratio (e.g., 4:1) and maintains high blood ketones (> 4 mmol/L). In addition, once started on the ketogenic diet, the child would stay on it for life. As “milder” cases of GLUT1, sometimes without seizures, have been identified, the reasons for maintain such a strict diet have been questioned. Articles have been published using the modified Atkins diet both after many years of ketogenic diet use and at the start of therapy with reported good success.

This past July, I had the pleasure of lecturing at the biannual GLUT1 Deficiency Foundation conference held in Houston, Texas. Both myself and our ketogenic dietitian from Johns Hopkins All Children’s Hospital in St. Petersburg, Florida, Ms. Stacey Bessone, spoke to nearly 100 parents about what we know about ketogenic diet use for GLUT1…and even more about what we don’t know! Information and lectures are available on their website – www.g1dfoundation.org. Several of the biggest, unanswered questions include:

  • Could the modified Atkins diet substitute for the traditional ketogenic diet for some children with GLUT1? This change seemed to be increasingly done according to parents for adolescents (and now even adults) with GLUT1 with good results.
  • Do ketones matter for children with GLUT1? Most of our families at Johns Hopkins only check urine ketones (and even after several years they stop that…), but for GLUT1 does the blood ketone level correlate with better success?
  • Will diets help the non-epilepsy aspects of GLUT1 (learning, movement disorders, etc.)? Are they even necessary?
  • After many years, as children with GLUT1 are now becoming young adults, is the diet no longer necessary for seizures and brain development? Can it be stopped?

It’s an exciting time for families with this rare, but very treatable condition. More research is coming, along with a proposed practice parameter to help guide diagnosis and treatment. In addition, the ketogenic diet support group Matthew’s Friends has partnered with the GLUT1 Deficiency Foundation to host a special session at the 2014 Liverpool, England, ketogenic diet meeting (see “Save the Date” below). The next GLUT1 meeting will be held in Orlando, Florida, from July 6 to 7, 2015. Families who are interested in meeting information should contact Glenna Steele at gsteele@g1dfoundation.org.

 

Save the Date

References

Klepper J, Leiendecker B. Glut1 deficiency syndrome and novel ketogenic diets. J Child Neurol. 2013 Aug;28(8):1045-8.

Leen WG, Mewasingh L, Verbeek MM, Kamsteeg EJ, van de Warrenburg BP, Willemsen MA. Movement disorders in Glut1 deficiency syndrome respond to the modified Atkins diet. Mov Disord. 2013 Sep;28(10):1439-42.

Verrotti A, D'Egidio C, Agostinelli S, Gobbi G. Glut1 deficiency: when to suspect and how to diagnose? Eur J Paediatr Neurol. 2012 Jan;16(1):3-9.

Authored by: Eric Kossoff MD on 11/2013
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