There are three inherited disorders of fructose metabolism that are recognized and characterized. Essential fructosuria, is a mild disorder not requiring treatment, while Hereditary fructose intolerance (HFI) and Hereditary fructose-1,6-biphosphatase deficiency (HFBP) are treatable and controllable but must be taken seriously.
Hereditary Fructose Intolerance (HFI) is an inherited inability to digest fructose (fruit sugar) or its precursors (sugar, sorbitol and brown sugar). This is due to a deficiency of activity of the enzyme fructose-1-phosphate aldolase, resulting in an accumulation of fructose-1-phosphate in the liver, kidney, and small intestine. Fructose is a naturally occurring sugar that is used as a sweetener in many foods, including many baby foods. This disorder can be life threatening in infants and ranges from mild to severe in older children and adults.
People who have HFI usually develop a strong dislike for sweets and fruit. After eating foods containing fructose, they may experience such symptoms as severe abdominal pain, vomiting, and low blood sugar (hypoglycemia).
Early diagnosis is important because, while most people who have HFI can lead normal lives if they adopt a fructose-free diet. If left untreated however, the condition can lead to permanent physical harm, including especially, serious liver and kidney damage.