title: Milder phenotypes of glucose transporter type 1 deficiency syndrome.
abstract: Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a treatable condition resulting from impaired glucose transport into the brain. The classical presentation is with infantile-onset epilepsy and severe developmental delay. Non-classical phenotypes with movement disorders and early-onset absence epilepsy are increasingly recognized and the clinical spectrum is expanding. The hallmark is hypoglycorrhachia (cerebrospinal fluid [CSF] glucose<2.2 mmol/l) in the presence of normoglycaemia with a CSF/blood glucose ratio of less than 0.4. GLUT1DS is due to a mutation in the solute carrier family 2, member 1 gene (SLC2A1). We present five individuals (four males, one female), all of whom had a mild phenotype, highlighting the importance of considering this diagnosis in unexplained neurological disorders associated with mild learning difficulties, subtle motor delay, early-onset absence epilepsy, fluctuating gait disorders, and/or dystonia. The mean age at diagnosis was 8 years 8 months. This paper also shows phenotypical parallels between GLUT1DS and paroxysmal exertion-induced dyskinesia.
authors.affiliation: Department of Paediatric Neurology, John Radcliffe Hospital, Oxford, UK. anandgeetha97@gmail.com
authors.forename: Geetha
authors.initials: G
authors.lastname: Anand
authors.forename: Anuruddha
authors.initials: A
authors.lastname: Padeniya
authors.forename: Donncha
authors.initials: D
authors.lastname: Hanrahan
authors.forename: Hans
authors.initials: H
authors.lastname: Scheffer
authors.forename: Zenobia
authors.initials: Z
authors.lastname: Zaiwalla
authors.forename: Debbie
authors.initials: D
authors.lastname: Cox
authors.forename: Nicholas
authors.initials: N
authors.lastname: Mann
authors.forename: John
authors.initials: J
authors.lastname: Hewertson
authors.forename: Sue
authors.initials: S
authors.lastname: Price
authors.forename: Andrea
authors.initials: A
authors.lastname: Nemeth
authors.forename: Todor
authors.initials: T
authors.lastname: Arsov
authors.forename: Ingrid
authors.initials: I
authors.lastname: Scheffer
authors.forename: Sandeep
authors.initials: S
authors.lastname: Jayawant
authors.forename: Michael
authors.initials: M
authors.lastname: Pike
authors.forename: Tony
authors.initials: T
authors.lastname: McShane
mesh_terms: D000293:Adolescent; D002239:Carbohydrate Metabolism, Inborn Errors / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004421:Dystonia / Q000235:genetics; D004832:Epilepsy, Absence / Q000235:genetics; D005260:Female; D005684:Gait; D005947:Glucose / Q000134:cerebrospinal fluid*; D051272:Glucose Transporter Type 1 / Q000235:genetics*; D006801:Humans; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000134:cerebrospinal fluid / Q000172:deficiency / Q000235:genetics; D009043:Motor Activity; D009154:Mutation; D010641:Phenotype; D012720:Severity of Illness Index
chemical_list: D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; C495677:SLC2A1 protein, human; D005947:Glucose