FASTING NORMOGLYCEMIA AND KETONE BODY FORMATION IN A CHILD WITH GLUCOSE-6-PHOSPHATASE DEFICIENCY

Abstract

108 Gycogenosis type-1a (GSD1a), due to glucose-6-phosphatase (G6P) deficiency, is usually associated with fasting hypoglycemia via defective glucose production (gluconeogenesis and glycogenolysis). Although patients with GSD-1a may generate some glucose from glycogen by a yet unclear mechanism, it is insufficient to prevent hypoglycemia. Whether ketone body (KB) formation occurs in GSD-1a remains controversial. We describe a 22 month old male infant with clinical, biochemical, histologic, histochemical and hepatic tissue enzyme and immunoblot analysis typical of GSD-1a, who tolerated prolonged fasting associated with KB formation while normalizing serum glucose and lactate levels. (Table) The unusual metabolic response to fasting in this child with GSD-1a was not due to residual G6P activity, as no immuno-reactivity for the G6P protein was detected. This case illustrates the phenotypic heterogeneity of this disorder and the need for further study into the mechanisms of energy production in hepatic glycogenoses.TABLE