Clinical characteristics and treatment analysis of children with glucose transporter type 1 deficiency syndrome: a report of two cases.

Abstract

Background: Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is a rare neurometabolic disorder caused by mutations in the SLC2A1 gene, leading to glucose transporter type 1 (GLUT1) dysfunction and cerebral energy failure. Clinically, it presents with intractable epilepsy, movement disorders, and developmental delay. Timely diagnosis remains challenging due to clinical heterogeneity.

Case description: We report two pediatric cases that presented with early-onset drug-resistant epilepsy, ataxia, and developmental delay. Case 1 presented with refractory epilepsy that was poorly responsive to antiseizure medications. Cerebrospinal fluid (CSF) analysis revealed hypoglycorrhachia (CSF glucose: 2.17 mmol/L; CSF-to-blood glucose ratio: 0.388). Genetic testing identified a heterozygous SLC2A1 variant (c.1198C>A, p.Arg400Ser), confirming GLUT1-DS. A ketogenic diet (KD) was initiated, leading to a significant reduction in seizure frequency. Case 2 presented with paroxysmal movement disorders and drug-resistant seizures. CSF analysis showed a glucose level of 2.27 mmol/L with a CSF-to-blood ratio of 0.315. SLC2A1 sequencing identified a mutation (c.988C>T, p.Arg330Ter). Following KD initiation, both patients showed significant clinical improvement (complete seizure freedom in Case 2 and marked reduction in Case 1), although long-term efficacy requires further monitoring.

Conclusions: A decreased CSF glucose level and a low CSF-to-blood glucose ratio are key diagnostic clues for GLUT1-DS. Early initiation of a KD yielded favorable short-term clinical outcomes in both cases, highlighting the importance of prompt metabolic and genetic screening.