title: Glycogen storage disease type Ia (GSDIa) but not Glycogen storage disease type Ib (GSDIb) is associated to an increased risk of metabolic syndrome: possible role of microsomal glucose 6-phosphate accumulation.
abstract: BACKGROUND
  In GSDIa, glucose 6-phosphate (G6P) accumulates in the endoplasmic reticulum (ER); in GSDIb, G6P levels are reduced in ER. G6P availability directly modulates the activity of 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1), an ER-bound enzyme playing a key role in the development of the metabolic syndrome (MS).
  
  
  OBJECTIVE
  To evaluate the prevalence of MS and Insulin Resistance (IR) in GSDIa and GSDIb patients.
  
  
  METHODS
  This was a prospective study. All the enrolled patients were followed at the Department of Pediatrics "Federico II" University of Naples for 10 years. Clinical and biochemical parameters of MS and the presence of IR were recorded. The results were correlated with the biochemical parameters of GSDI-related metabolic control. 10 GSDIa patient (median age 12.10 ± 1.50), 7 GSDIb patients (median age 14.90 ± 2.20 were enrolled in the study. They were compared to 20 and 14 age and sex matched controls, respectively. 10 GSDIa patients (median age 24.60 ± 1.50) and 6 GSDIb patients (median age 25.10 ± 2.00) completed the 10-year-follow-up. At the end of the study the patients' data were compared to 10 and 6 age and sex matched controls, respectively.
  
  
  RESULTS
  At study entry, 20 % GSDIa patients had MS and 80 % showed 2 criteria for MS. GSDIa patients showed higher HOMA-IR than controls and GSDIb patients (p < 0.001, p < 0.05), respectively. Baseline ISI was lower in GSDIa than controls (p < 0.001). QUICKI was significantly lower in GSDIa than in controls (p < 0.001). At the end of the study 70 % of GSDIa patients had MS and 30 % showed 2 criteria for MS. HOMA-IR was higher in GSDIa than controls (p < 0.01). Baseline ISI was higher in GSDIb than controls (p < 0.005) and GSD1a (p < 0.05). QUICKI was lower in GSD1a patients than in controls (p < 0.03). VAI was higher in GSDIa patients than controls (p < 0.001) and GSDIb patients (p = 0.002).
  
  
  CONCLUSIONS
  Our data showed high prevalence of IR and MS in GSDIa patients. We speculate a possible role of 11βHSD1 modulation by G6P availability. We suggest a routine metabolic assessment in GSDIa patients.
authors.affiliation: Department of Pediatrics, Azienda Ospedaliera Universitaria "Federico II", Via Sergio Pansini, 5 80131, Naples, Italy. daniela.melis@unina.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Melis
authors.affiliation: Department of Translational Medical Sciences, Section of Pediatrics, "Federico II" University, Naples, Italy. ale.ro_ar@libero.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rossi
authors.affiliation: Department of Medicine and Surgery, Section of Endocrinology, "Federico II" University, Naples, Italy. rosario.pivonello@unina.it.
authors.forename: Rosario
authors.initials: R
authors.lastname: Pivonello
authors.affiliation: Department of Translational Medical Sciences, Section of Pediatrics, "Federico II" University, Naples, Italy. salerno@unina.it.
authors.forename: Mariacarolina
authors.initials: M
authors.lastname: Salerno
authors.affiliation: Department of Translational Medical Sciences, Section of Pediatrics, "Federico II" University, Naples, Italy. francescabalivo@libero.it.
authors.forename: Francesca
authors.initials: F
authors.lastname: Balivo
authors.affiliation: Department of Translational Medical Sciences, Section of Pediatrics, "Federico II" University, Naples, Italy. s.spadarella@hotmail.it.
authors.forename: Simona
authors.initials: S
authors.lastname: Spadarella
authors.affiliation: Department of Medicine and Surgery, Section of Endocrinology, "Federico II" University, Naples, Italy. giovanna.muscogiuri@gmail.com.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Muscogiuri
authors.affiliation: Department of Translational Medical Sciences, Section of Pediatrics, "Federico II" University, Naples, Italy. roberto.dellacasa@unina.it.
authors.forename: Roberto Della
authors.initials: RD
authors.lastname: Casa
authors.affiliation: Department of Translational Medical Sciences, Section of Clinical Pathology, "Federico II" University, Naples, Italy. fpietro@unina.it.
authors.forename: Pietro
authors.initials: P
authors.lastname: Formisano
authors.affiliation: Department of Pediatrics, Azienda Ospedaliera Universitaria "Federico II", Via Sergio Pansini, 5 80131, Naples, Italy. andria@unina.it.
authors.forename: Generoso
authors.initials: G
authors.lastname: Andria
authors.affiliation: Department of Medicine and Surgery, Section of Endocrinology, "Federico II" University, Naples, Italy. colao@unina.it.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Colao
authors.affiliation: Department of Translational Medical Sciences, Section of Pediatrics, "Federico II" University, Naples, Italy. parenti@unina.it.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Parenti
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D004198:Disease Susceptibility; D005260:Female; D019298:Glucose-6-Phosphate / Q000378:metabolism*; D005953:Glycogen Storage Disease Type I / Q000150:complications*; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000209:etiology*; D008861:Microsomes / Q000378:metabolism*; D011446:Prospective Studies
chemical_list: D019298:Glucose-6-Phosphate