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Indian Pediatr 2015;52: 997 |
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Intermittent Ataxia with Early Onset Absence
Epilepsy in Glucose Transporter
Type 1 Deficiency Syndrome
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Vykuntaraju K Gowda and Sukrita Sheshu
Bangalore Child Neurology and Rehabilitation Center,
Vijayanagar, Bengaluru, India
Email: [email protected]
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A 4-year-old girl, born to healthy non consanguineous parents after an
uneventful pregnancy and delivery with normal birth weight, presented
with history of absence seizures and ataxia since 7 months of age.
Absence seizures and ataxia were worse in the fasting state. She was
otherwise able to walk and run, and had a normal speech. On examination,
she had microcephaly (head circumference 46 cm); the tone was normal and
deep tendon reflexes were brisk. She had mild ataxia.
A combination of early onset absence seizures with
ataxia which were more prominent in fasting state led us to a suspicion
of Glucose Transporter Type I (GLUT 1) Deficiency Syndrome. We
considered other differential diagnoses like idiopathic early onset
absence epilepsy, inborn errors of metabolism, episodic ataxia and
cortical malformations. Cerebrospinal fluid (CSF) examination showed low
glucose (30 mg/dL) compared to blood glucose (87mg/dL).
Electroencephalography (EEG) showed generalized 2-3 Hz, 100-300 micro
volts spikes, sharp waves and poly spike discharges. Arterial blood gas
analysis, ammonia and tandem mass spectrometry were normal. Magnetic
resonance imaging (MRI) of the brain was also normal. GLUT1 deficiency
was confirmed with a missense mutation p.Thr295Met in exon 7 SCL2A1
gene. The child was started on ketogenic diet following which the child
became seizure free. The ataxia improved over a period of 4-5 weeks.
The classic phenotype in GLUTI deficiency is
infantile onset seizures, delayed neurological development and acquired
microcephaly [1]. Cases with early onset absence epilepsy, intermittent
ataxia, choreoathetosis, and dystonia and West syndrome have also been
described [1,2]. The missense mutations are associated with mild to
moderate clinical phenotypes [3]. There are few cases described in
literature that share the same mutation as described in this child [4].
In summary, GLUT1 deficiency syndrome should
be suspected in any child presenting with intermittent ataxia and early
onset absence seizures which are more prominent in the fasting state.
Ketogenic diet in these patients can prevent long-term morbidity.
References
1. Wang D, Pascual JM, De Vivo D. Glucose Transporter
Type 1 Deficiency Syndrome. 2002 Jul 30 [Updated 2015 Jan 22]. In:
Pagon RA, Adam MP, Ardinger HH, et al., editors.
GeneReviews® [Internet]. Seattle (WA): University of Washington,
Seattle; 1993-2015. Available from:
http://www.ncbi.nlm.nih.gov/books/NBK1430/ Accessed May 25, 015.
2. Gowda VK, Bhat S, Sanjay KS, Govindraju M.
Symptomatic West syndrome secondary to Glucose Transporter -1(GLUT1)
deficiency with complete response to 4:1 ketogenic diet. Indian J
Pediatr. 2014;81:934-6.
3. Yang H, Wang D, Engelstad K, Bagay L, Wei Y,
Rotstein M, et al. Glut1 deficiency syndrome and erythrocyte
glucose uptake assay. Ann Neurol. 2011;70:996-1005.
4. Anand G, Padeniya A, Hanrahan D, Scheffer H,
Zaiwalla Z, Cox D, et al. Milder phenotypes of glucose
transporter type 1 deficiency syndrome. Dev Med Child Neurol.
2011;53:664-8.
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