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Re: GLUT 1 deficiency syndome is seldom a neonatal problem

Dear Editor,

In their leading article on Treatable Neonatal Epilepsy, Surtees and Wolf list the syndrome of glucose transporter deficiency Type 1 (GLUT 1) as the second entry on their list of metabolic causes of early onset epilepsy(1). I think that this could mislead many practitioners into thinking that seizures affecting infants in the first few weeks of life could be due to this disorder.

I am not aware of any cases reported in which seizures occurred so early in life. Leary et al described 20 affected patients, mean age of seizure onset was 5 months, with a range of 1-18 months (2). Klepper & Voit emphasise that in GLUT-1 deficiency syndrome "the majority of patients, delivery and the neonatal period are normal".(3).

The preferred treatment of GLUT 1 deficiency syndrome is ketogenic diet and I wonder whether this is precisely the reason why neurological abnormalities do not occur in the neonatal period, even when the metabolic abnormality is present. The neonatal brain appears adapted to utilizing ketone bodies as an energy source in times of glucose scarcity, also the expression of GLUT 1 can be upregulated at times of stress (4), both reasons why seizures may not occur in the neonatal period in patients with GLUT 1 deficiency disorder.

GLUT 1 deficiency syndrome is an important treatable cause of recurrent seizures and neurological abnormalities, and is diagnosed initially by the finding of hypoglycorrhachia, but not in the newborn.

References:

1) Surtees R, Wolf N Treatable neonatal epilepsy Arch Dis Child 2007; 92: 659-661.

2) Leary LD, Wang D, Nordli D R, Engelstad K, De Vivo D Seizure characterization and electroencephalographic features in Glut-1 deficiency syndrome Epliepsia 2003; 44(5): 701-7.

3) Klepper J, Voit T. Facilitated glucose transporter protein type 1 (GLUT1) deficiency syndrome: impaired glucose transport into brain-a review Eur J Pediatr 2002; 161: 295-304.