Fig. 1.

Schematic metabolism of monosaccharides metabolism and the impact on GSD-Ia. After carbohydrate ingestion, the monosaccharides (D-glucose, D-fructose and D-galactose) lead to the formation of D-glucose-6-phosphate. Due to the deficient activity of the glucose-6-phosphatase enzyme, the D-glucose remains in the intracellular fluid, thus stimulating the glycogen formation, ultimately causing hypoglycemia and an excessive production of lactate. GSD1a: glycogen storage disease type 1a; P: phosphate; TCA: tricarboxylic acid cycle