Question

An 18-month-old is newly diagnosed with hereditary fructose intolerance (deficiency in Aldolase B). His mother reports he is particularly upset when he gets up in the morning or if he has not eaten in a while. Laboratory testing showed low blood glucose levels at the time of presentation. This presentation is likely due to an accumulation of fructose 1 -phosphate and inhibition of which of the following pathways?

Answer 1

The presentation of an 18-month-old with hereditary fructose intolerance (HFI), deficiency of aldolase B and low blood glucose levels is due to accumulation of fructose-1 phosphate and the inhibition of glycolytic-gluconeogenic pathways.

Explanation:

Hereditary fructose intolerance leads to deficiency of fructose-1-phosphate aldolase enzyme. This enzyme deficiency leads to accumulation of fructose-1 phosphate in the liver. Fructose-1 phosphate inhibits the action of phosphorylase enzyme which monitors the glycogen to glucose conversion. Since glucose formation is reduced, hypoglycemia and lactic acidosis takes place accounting for the patient’s low blood sugar.