Question

A 3-year-old boy is brought to the emergency department after several episodes of vomiting and lethargy. As his
pediatrician you were concerned about his failure to thrive and possible hepatic failure along with recurrent
episodes of the vomiting and lethargy. After a careful history is taken, you observe that these episodes occur after
ingestion of certain types of food, particularly fruits or anything high in fructose. His blood sugar was checked in
the emergency department and was extremely low.

Q) Discuss the derangements in the biochemical pathways ? why?

Answer 1

This is a condition of Hereditary fructose intolerance .HFI is a metabolic disease which occur due to the absence of enzyme Aldolase B.

In Child with HFI--Ingestion of fructose Can causes severe hypoglycemia & build up of Toxic substances in the liver.

In normal Condition--

Fructose----Fructose 1 Phosphate(By enzyme Fructokinase)

The enzyme Aldolase B Cleaves Fructose 1 Phosphate-----Glyceraldehyde & Dihydroxyacetone Phosphate.

Glyceraldehyde-----Glyceraldehyde 3 Phosphate (By Triose Kinase).

Dihydroxyacetone Phosphate-----Glyceraldehyde 3 Phosphate(By triose phosphate isomerase)

Glyceraldehyde Eventually Forms Pyruvate.

From Puryvate Gluconeogenesis or Glycolysis Can occur.

In Absence of Aldolase B---

Fructose 1 Phosphate-----Glyceraldehyde & Dihydroxyacetone Phosphate donot happen

So there is Accumulation of Fructose 1 Phosphate

This Inhibits Gluconeogenesis & Glycolysis Leading to Hypoglycemia.

Also Causes Toxicity in Liver kidney and Small intestine