title: [Clinical and genetic characteristics of glucose transporter type 1 deficiency syndrome].
abstract: OBJECTIVE
  To analyze the clinical and SLC2A1 gene mutation characteristics of glucose transporter type 1 deficiency syndrome.
  
  
  METHODS
  The detailed clinical manifestations of six cases were recorded. The laboratory tests including EEG, MRI, blood chemistry, and lumbar puncture were performed. SLC2A1 gene mutations were analyzed by PCR, DNA sequencing and multiplex ligation-dependent probe amplification (MLPA).
  
  
  RESULTS
  Patient 1, 2 and 3 had classical clinical symptoms including infantile onset seizures, development delay. Patient 4, 5 and 6 had non-classical clinical symptoms including paroxysmal behavior disturbance, weakness, ataxia, lethargy, especially after fasting or exercise, without severe seizures. The plasma glucose levels were normal. The CSF glucose levels decreased in all the six cases, ranged from 1.10 mmol/L to 2.45 mmol/L, the mean level was 1.68 mmol/L. The CSF glucose/plasma glucose ratios decreased, ranged from 0.16 to 0.51, the mean ratio was 0.34. Four patients had normal EEG. Two patients had focal and diffuse epileptiform discharge, and one of them also had paroxysmal occipital or generalized high-amplitude slow waves during awake and sleep time. MRI abnormalities were found in three patients, patient 1 with mild brain atrophy, patient 3 with bilateral ventricle plump, and patient 4 with high signals in T2 in the frontal and occipital white matter, interpreted as hypomyelination. SLC2A1 gene mutations were found in six cases. Patient 1 has large scale deletion in exon 2. In patient 2 to 6, the mutations were c.741 G>A (E247K), 599delA, 761delA, c.1148 C>A (P383H), c.1198 C>T (R400C) respectively. Two patients were treated with ketogenic diet. The seizures disappeared and development became normal. Three patients responded to frequent meals with snacks. One patient refused any treatments, the symptoms continued to exist.
  
  
  CONCLUSIONS
  The clinical manifestations of glucose transporter type 1 deficiency syndrome are varied. The common symptoms included infantile onset seizures and various paroxysmal events. These neurologic symptoms generally fluctuated and were influenced by factors such as fasting or fatigue. This feature could be a very important clue for the diagnosis of GLUT1-DS. Lumbar puncture is recommended in patients with episodic CNS symptoms especially after fasting. GLUT1-DS is a treatable neurometabolic disorder, early diagnosis and treatment may improve the prognosis of the patients.
authors.affiliation: Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
authors.forename: Yan-yan
authors.initials: YY
authors.lastname: Liu
authors.forename: Xin-hua
authors.initials: XH
authors.lastname: Bao
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.forename: Na
authors.initials: N
authors.lastname: Fu
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Liu
authors.forename: Fu-ying
authors.initials: FY
authors.lastname: Song
authors.forename: Yan-ling
authors.initials: YL
authors.lastname: Yang
authors.forename: Ye
authors.initials: Y
authors.lastname: Wu
authors.forename: Yue-hua
authors.initials: YH
authors.lastname: Zhang
authors.forename: Jian-xin
authors.initials: JX
authors.lastname: Wu
authors.forename: Yu-wu
authors.initials: YW
authors.lastname: Jiang
authors.forename: Jiong
authors.initials: J
authors.lastname: Qin
authors.forename: Xi-ru
authors.initials: XR
authors.lastname: Wu
mesh_terms: D015415:Biomarkers / Q000032:analysis; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002239:Carbohydrate Metabolism, Inborn Errors / Q000175:diagnosis* / Q000235:genetics* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D055423:Diet, Ketogenic; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis / Q000235:genetics / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D051272:Glucose Transporter Type 1 / Q000235:genetics*; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000172:deficiency* / Q000235:genetics; D009069:Movement Disorders / Q000175:diagnosis / Q000235:genetics / Q000628:therapy; D009154:Mutation / Q000235:genetics*; D011859:Radiography
chemical_list: D015415:Biomarkers; D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; C495677:SLC2A1 protein, human