Glycogen storage disease: clinical diagnosis and nutritional management

Abstract

Glycogen storage diseases (GSD) are inborn errors of metabolism due to deficiencies in one of the enzymes involved in glycogen synthesis or degradation. We describe the clinical and laboratory findings of 6 children aged 13-52 months with GSD types III, VI or IX and the short term results of dietary therapy. 5 children presented with massive hepatomegaly and one with seizures secondary to hypoglycaemia. The diagnosis was confirmed by an oral glucose loading test, during which all patients showed marked postprandial hperlactacidaemia, a liver biopsy that confirmed the intracellular glycogen accumulation and in 3 children with specific enzyme assays. All children had elevated liver enzymes and hyperlipidaemia at the time of diagnosis. They were started on a frequent feeding low fat diet. After 6 months we observed an improvement of the lipid profile, with reduction in total cholesterol of 19% and an increase in HDL-cholesterol of 55% compared to baseline values. GSD should be considered in the differential diagnosis of children presenting with "apparently asymptomatic" hepatomegaly, particularly if associated with dyslipidaemia. The use of selected laboratory tests, such as the glucose loading challenge, allows the confirmation of the suspected diagnosis and the adequate use of invasive testing.