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Background: Of the patients with glucose transporter 1 deficiency syndrome (GLUT1-DS), 90% have a pathologic gait. Ataxic-spastic and ataxic gaits are seen in 35% of patients each. A ketogenic diet and modified Atkins diet (MAD) are effective therapy in GLUT1-DS in terms of both the seizures and movement disorder. A three-dimensional gait analysis (3DGA) system can be used to evaluate gait quantitatively using spatiotemporal data and gait kinematics. We performed 3DGA in three ambulatory patients with GLUT1-DS to evaluate the characteristics of their gait pathology, and we compared the gait variables before and after enhancing the MAD in one patient.Methods: After examination by pediatric neurologists and pediatric orthopedic surgeons, 3DGA was performed. We assessed walking speed, step length, step width, gait variability, Gait Deviation Index (GDI), Gait Profile Score (GPS), and Gait Variable Score (GVS).Results: All three patients had a low GDI and high GPS, comprehensive indices of gait pathology. The unstable gait pattern featured a wide step width in one patient and high gait variability in two patients. In the sagittal plane, the patients had increased GVSs in the knee and ankle joints due to excessive knee flexion or extension and excessive ankle plantarflexion. In the horizontal plane, the patients had increased GVSs in the pelvis, hips, and foot due to excessive rotation during walking. After enhancing the MAD, GDI, GPS, and GVSs improved.Conclusions: 3DGA has potential for quantifying the characteristics of gait pathology and its improvement with dietary therapy in patients with GLUT1-DS. [ABSTRACT FROM AUTHOR]

Background: As is often the case for rare diseases, the number of published reviews and case reports of glucose transporter type I deficiency (G1D) approaches or exceeds that of original research. This can indicate medical interest, but also scientific stagnation.Methods: In assessing this state of affairs here, we focus not on what is peculiar or disparate about G1D, but on the assumptions that have reigned thus far undisputed, and critique them as a potential impediment to progress. To summarize the most common G1D phenotype, we trace the 25-year story of G1D in parallel with the natural history of one of two index patients, identified in 1990 by one of us (G.M.R.) and brought up to date by the other (J.M.P.) while later examining widely repeated but little-scrutinized statements. Among them are those that pertain to assumptions about brain fuels; energy failure; cerebrospinal glucose concentration; the purpose of ketogenic diet; the role of the defective blood-brain barrier; genotype-phenotype correlations; a bewildering array of phenotypes; ictogenesis, seizures, and the electroencephalograph; the use of mice to model the disorder; and what treatments may and may not be expected to accomplish.Results: We reach the forgone conclusion that the proper study of mankind-and of one of its ailments (G1D) -is man itself (rather than mice, isolated cells, or extrapolated inferences) and propose a framework for rigorous investigation that we hope will lead to a better understanding and to better treatments for this and for rare disorders in general.Conclusions: These considerations, together with experience drawn from other disorders, lead, as a logical consequence, to the nullification of the view that therapeutic development (i.e., trials) for rare diseases could or should be accelerated without the most vigorous scientific scrutiny: trial and error constitute an inseparable couple, such that, at the present time, hastening the former is bound to precipitate the latter. [ABSTRACT FROM AUTHOR]

Objective Glucose transporter 1 deficiency syndrome is an autosomal, dominantly inherited neurometabolic disorder caused by mutations in the SLC2A1 gene. Decreased glucose transport into the brain results in seizures and cognitive dysfunction. The ketogenic diet is the treatment of choice, but complicated with compliance problems. Stabilization of blood glucose levels by low glycemic index diet and modified high amylopectin cornstarch would provide steady-state glucose transport into the brain to prevent seizures and cognitive dysfunction in patients with glucose transporter 1 deficiency syndrome as an alternative treatment. Patient We report a new glucose transporter 1 deficiency syndrome patient (c.988C>T; p. Arg330X in the SLC2A1 ) treated with modified high amylopectin cornstarch (Glycosade) and low glycemic index diet because of compliance problems with the ketogenic diet. She was diagnosed at 11.5 years of age and was treated with the ketogenic diet between ages 12 and 18 years. Results She was started on modified high amylopectin cornstarch at bedtime and low glycemic index diet with meals and snacks every 3-4 hours. Within the first 6 months of therapy, she improved in her seizures and cognitive functions, but experienced compliance problems afterwards. Neuropsychological assessment was stable at 12 months of therapy. Conclusion This diet was easy to apply compared with the ketogenic diet and resulted in stable neuropsychological functioning of this glucose transporter 1 deficiency syndrome patient. Modified high amylopectin cornstarch and low glycemic index diet might be an alternative treatment in glucose transporter 1 deficiency syndrome patients with compliance problems to the ketogenic diet treatment, but additional patients should be treated to prove usefulness of this new treatment. [ABSTRACT FROM AUTHOR]

Abstract: Background: Glucose transporter type 1 deficiency syndrome is caused by brain energy failure resulting from a disturbance in glucose transport. Patients: We describe a 4-year-old boy with classical type glucose transporter type 1 deficiency syndrome with a heterozygous splice acceptor site mutation (c.517-2A>G) in the SLCA2A1 gene. Results: We initiated a ketogenic diet at 4 months of age. However, even though his condition was good during ketogenic diet therapy, multiple cerebral white matter and right cerebellum lesions appeared at 9 months of age. The lesions in the cerebral white matter subsequently disappeared, indicating that white matter lesions during diet therapy may be reversible and independent of the ketogenic diet. Conclusions: This is the first report of reversible white matter lesions during ketogenic diet therapy in glucose transporter type 1 deficiency syndrome. [Copyright &y& Elsevier]

Background: Epileptic myoclonus in infancy is associated with various pathological conditions. In the absence of an identifiable central nervous system lesion, an underlying metabolic genetic cause is often suspected.Patients: We describe two infants with glucose transporter 1 deficiency syndrome who presented with epileptic myoclonus. One infant presented with an electroclinical phenotype mimicking benign myoclonic epilepsy of infancy; the other infant had a novel mutation and presented with opsoclonus and epileptic myoclonus with a robust response to high-dose steroids. Both infants began the ketogenic diet after the diagnosis of glucose transporter 1 deficiency syndrome, with good yet variable treatment responses.Conclusions: These infants demonstrate that an evaluation for glucose transporter 1 deficiency syndrome is warranted in patients presenting with an electroclinical picture compatible with benign myoclonic epilepsy of infancy as well as in patients with intractable epilepsy who demonstrate a significant response to steroid therapy. [ABSTRACT FROM AUTHOR]

Abstract: Background: Alternating hemiplegia of childhood (AHC) is a rare condition characterized by an early onset of hemiplegic episodes and other paroxysmal or permanent neurological dysfunctions. Recently, mutations in the ATP1A3 gene have been identified as the causal mechanism of AHC. Regarding the differential diagnosis of AHC, glucose transporter 1 deficiency syndrome may be considered because these two disorders share some paroxystic and nonparoxystic features. Patient and results: We report a typical case of AHC harboring a de novo mutation in the ATP1A3 gene, together with a duplication and insertion in the SLC2A1 gene who exhibited marked clinical improvement following ketogenic diet. Conclusion: Because the contribution of the SLC2A1 mutation to the clinical phenotype cannot be definitely demonstrated, the remarkable clinical response after ketogenic diet led us to the hypothesis that ketogenic diet might be effective in AHC as it provides an alternative energy source for the brain. [Copyright &y& Elsevier]

Abstract: Introduction: Glucose transporter type 1 deficiency syndrome is a metabolic encephalopathy that results from impaired glucose transport into the brain as the result of a mutation of the SLC2A1 gene. It has been recognized recently that these patients can present with a much broader clinical spectrum than previously thought. We describe a 3-year-old boy presenting with episodic ataxia. Case Report: Our patient exhibited periodic abnormal eye movements, including opsoclonus, since he was 4 months of age. At 2 years of age, he experienced acute cerebellar ataxia after a vaccination. Since then, he has had periodic attacks of ataxic gait, repeated vomiting, and abnormal eye movement. He was diagnosed as having episodic ataxia type 2 because the administration of acetazolamide seemed effective. By 3 years and 10 months of age, he exhibited mild mental retardation and mild trunk ataxia. The attacks were more likely to occur when he was hungry. Molecular analysis revealed that the SLC2A1 gene had a de novo mutation of heterozygous seven nucleotide insertion within exon 7, resulting in a frameshift. He has recently begun a modified Atkins diet; the frequency of attacks has been reduced, and his psychomotor and language skills have begun to develop. Discussion: Glucose transporter type 1 deficiency syndrome should be considered in the differential diagnosis in children with episodic ataxia, even if acetazolamide is effective. [Copyright &y& Elsevier]