In an article published in the Archives of Neurology the authors aim to describe Neuroglycopenia as a specific syndrome caused by insufficient glucose availability during brain development. They describe a phenotype characterised by a combination of infantile epilepsy, mental retardation, and abnormal movement coordination and tone, together with a pattern of cerebral–gray matter abnormalities detectable by PET scanning.

Juan M. Pascual et al in the article Brain Glucose Supply and the Syndrome of Infantile Neuroglycopenia published in Arch Neurol Feb 12, 2007 performed Neurologic examinations, neuropsychologic tests, biochemical methods, and PET imaging on patients afflicted by genetic mutation of the cerebral glucose transporter type 1 and a patient afflicted by persistent infantile hypoglycemia (hyperinsulinism) .

They concluded that neuroglycopenia in the developing brain, caused aberrant maturation of the thalamic and cortical metabolism resulting in, characteristic neurologic and behavioral disturbances including epilepsy. These changes were seen in functional imaging as well. Following maturation, glucose serves as a fuel and disturbances caused by its undeficiency seems to be unrelated.

According to the authors the combination of infantile epilepsy, mental retardation, and abnormal movement coordination and tone, together with a pattern of cerebral–gray matter abnormalities detectable by PET scanning constitutes the syndrome of neuroglycopenia and suggests persistent hypoglycemia and molecular deficits in the GLUT1 gene as the major mechanisms.

In infancy, the fundamental manifestation of neuroglycopenia is epilepsy that is refractory to medications and deceleration of head growth. Abnormalities of ocular movement resembling opsoclonus (which can be particularly prominent in GLUT1 deficiency), alterations of muscle tone, articulatory language dysfunction, and movement disorders (including ataxia and dystonia) are commonly associated.

After childhood, the residual clinical pattern is dominated by spasticity, ataxia, and language difficulties, with or without epilepsy. In GLUT1 deficiency, these clinical features are often associated with generalized 2.5- to 3.5-Hz spike-wave electroencephalographic discharges14 and with normal brain structure as assessed by magnetic resonance imaging. Measures of neuropsychologic performance are invariably abnormal.

The mechanisms of neuroglycopenic brain development and function remain to be elucidated. However these findings as the authors suggest, may indicate that glucose may act in a dual capacity, both as fuel and as a signaling molecule, causing a more selective spectrum of abnormalities than just those attributed to a global energy substrate deficiency.

Boles RG, Seashore MR, Mitchell WG, Kollros PR, et al. Glucose transporter type 1 deficiency: a study of two cases with video-EEG. Eur J Pediatr 1999;158:978-983.

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