Future research should focus on subpopulations of focal epilepsy with lower age of seizure onset particularly with co-existent movement disorders in which GLUT1 mutations may play a more important role.
Glucose transporter type 1 deficiency syndrome (Glut-1DS) is caused by autosomal dominant haplodeficiency or autosomal recessive with homozygous mutation of the glucose transporter 1 (SLC2A1) gene and is characterized by severe seizures, developmental delay, ataxia and acquired microcephaly.
A part from this classic phenotype, clinical conditions associated with a deficiency of GLUT1 are highly variable and several atypical variants have been described; in particular, patients with movement disorders, but without seizures, with paroxysmal exertion-induced dyskinesia, have been reported.
Here a remarkable immediate and effective seizure control and a dose-independent unsuccessful steroid withdrawal indicated a potential GLUT1 sensitivity to steroids.
Our purpose is (1) to describe epilepsy phenotypes in a large Glut 1 DS cohort, to facilitate diagnosis; and (2) to describe cases in which non-KD agents achieved seizure freedom (SF), highlighting potential adjunctive treatments.
We analyzed the SLC2A1 gene in 12 Japanese Glut1-DS patients who were diagnosed by characteristic clinical symptoms and hypoglycorrhachia as follows: all patients had infantile-onset seizures and mild to severe developmental delay, and ataxia was detected in 11 patients.
GLUT1-DS is characterized by movement disorders, including paroxysmal exercise-induced dystonia (PED), as well as seizures, mental retardation and hypoglycorrhachia.
Glucose transporter type I deficiency syndrome (GLUT-1 DS) is an inborn error of glucose transport characterized by seizures, developmental delay, spasticity, acquired microcephaly and ataxia.
In 2002, we identified a heterozygous missense mutation substituting glycine at residue 75 for tryptophan in a 10-year-old girl with intractable seizures and low glucose concentrations in the cerebrospinal fluid indicative of GLUT1 deficiency.
Fifteen children presenting with infantile seizures, acquired microcephaly, and developmental delay were found to have novel heterozygous mutations in the GLUT1 (SLC2A1).