Evaluation of glycogen storage disease as a cause of ketotic hypoglycemia in children.

INTRODUCTION: Ketone formation is a normal response when hypoglycemia occurs. Since the majority of children with recurrent hypoglycemia cannot be diagnosed with a known endocrine or metabolic disorder on a critical sample, ketotic hypoglycemia has been described as the most common cause of low blood glucose concentrations in children. Critical samples, however, will miss the ketotic forms of glycogen storage disease (GSD), which present with elevated ketones, hypoglycemia, and normal hormonal concentrations. RESULTS: A total of 164 children (96 boys, 68 girls) were enrolled in the study. Prediction of pathogenicity of DNA changes using computer modeling confirmed pathology in 20 individuals [four GSD 0, two GSD VI, 12 GSD IX alpha, one GSD IX beta, one GSD IX gamma] (12%). Boys were most likely to have changes in the PHKA2 gene, consistent with GSD IX alpha, an X-linked disorder. CONCLUSIONS: Mutations in genes involved in glycogen synthesis and degradation were commonly found in children with idiopathic ketotic hypoglycemia. GSD IX is likely an unappreciated cause of ketotic hypoglycemia in children, while GSD 0 and VI are relatively uncommon. GSD IX alpha should particularly be considered in boys with unexplained hypoglycemia.

Characterization and pathogenesis of anemia in glycogen storage disease type Ia and Ib.

PURPOSE: The aim of this study was to characterize the frequency and causes of anemia in glycogen storage disease type I. METHODS: Hematologic data and iron studies were available from 202 subjects (163 with glycogen storage disease Ia and 39 with glycogen storage disease Ib). Anemia was defined as hemoglobin concentrations less than the 5th percentile for age and gender; severe anemia was defined as presence of a hemoglobin <10 g/dl. RESULTS: In glycogen storage disease Ia, 68/163 patients were anemic at their last follow-up. Preadolescent patients tended to have milder anemia secondary to iron deficiency, but anemia of chronic disease predominated in adults. Severe anemia was present in 8/163 patients, of whom 75% had hepatic adenomas. The anemia improved or resolved in all 10 subjects who underwent resection of liver lesions. Anemia was present in 72% of patients with glycogen storage disease Ib, and severe anemia occurred in 16/39 patients. Anemia in patients with glycogen storage disease Ib was associated with exacerbations of glycogen storage disease enterocolitis, and there was a significant correlation between C-reactive protein and hemoglobin levels (P = 0.036). CONCLUSION: Anemia is a common manifestation of both glycogen storage disease Ia and Ib, although the pathophysiology appears to be different between these conditions. Those with severe anemia and glycogen storage disease Ia likely have hepatic adenomas, whereas glycogen storage disease enterocolitis should be considered in those with glycogen storage disease Ib.

Natural history of hepatocellular adenoma formation in glycogen storage disease type I.

OBJECTIVE: To characterize the natural history and factors related to hepatocellular adenoma (HCA) development in glycogen storage disease type Ia (GSD Ia). STUDY DESIGN: Retrospective chart review was performed for 117 patients with GSD Ia. Kaplan-Meier analysis of HCA progression among two groups of patients with GSD Ia (5-year mean triglyceride concentration ≤ 500 mg/dL and >500 mg/dL); analysis of serum triglyceride concentration, body mass index SDS, and height SDS between cases at time of HCA diagnosis and age- and sex-matched control subjects. RESULTS: Logrank analysis of Kaplan-Meier survival curve demonstrated a significant difference in progression to HCA between the 5-year mean triglyceride groups (P = .008). No significant difference was detected in progression to adenoma event between sexes. Serum triglyceride concentration was significantly different at time of diagnosis of adenoma (737 ± 422 mg/dL) compared with control subjects (335 ± 195 mg/dL) (P = .009). Differences in height SDS (P = .051) and body mass index SDS (P = .066) approached significance in our case-control analysis. CONCLUSION: Metabolic control may be related to HCA formation in patients with GSD Ia. Optimizing metabolic control remains critical, and further studies are warranted to understand the pathogenesis of adenoma development.