Hereditary fructose intolerance

[Becky]

Hereditary fructose intolerance is a carbohydrate metabolism disorder that is caused by a lack of the enzyme needed to metabolize fructose. Very small amounts of fructose cause low blood sugar levels and can lead to kidney and liver damage. Fructose intolerance disorders occur when parents pass the defective genes that cause these disorders on to their children.

Fructose intolerance is caused by the lack of an enzyme needed to break down fructose.
Typical symptoms include low blood sugar, sweating, confusion, and kidney damage.
The diagnosis is made by analyzing a sample of liver tissue.
Treatment includes avoiding fructose in the diet and, when needed, taking glucose tablets.

Fructose is a sugar present in table sugar (sucrose), honey, and many fruits. Fructose is also present in sorbitol (a sugar substitute).
Children who have one of these disorders are missing one of the enzymes needed to break down (metabolize) fructose. As a result, a by-product of fructose accumulates in the body, blocking the formation of glycogen and its conversion to glucose for use as energy.
There are different types of inherited disorders. In hereditary fructose intolerance, both parents of the affected child carry a copy of the abnormal gene. Because usually two copies of the abnormal gene are necessary for the disorder to occur, usually neither parent has the disorder. (See also Overview of Hereditary Metabolic Disorders.)