Hereditary fructose intolerance

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Fructose intolerance Classification and external resources
Fructose
ICD-10	E74.1
ICD-9	271.2
OMIM	229600
DiseasesDB	5003
MedlinePlus	000359
eMedicine	ped/988
MeSH	D005633

Hereditary fructose intolerance (HFI) or fructose poisoning is a hereditary condition caused by a deficiency of liver enzymes that metabolise fructose. It is also known as hereditary fructosemia, or fructose in the blood (-emia means in the blood)

Contents 1 Causes 2 Presentation 3 Treatment 4 Related conditions 5 See also 6 References 7 External links

[edit] Causes

The deficient enzyme is aldolase-B, which converts fructose-1-phosphate to DHAP and glyceraldehyde. This means that the fructose cannot be further metabolised beyond fructose-1-phosphate. This traps phosphates; which are needed to phosphorylate glycogen phosphorylase which carries on to release units of glucose-1-phosphate from glycogen. (Glucose-1-phosphate gets converted to glucose-6-phosphate and then dephosphorylated to form glucose).

In addition, Aldolase A plays an important role in gluconeogenesis, producing fructose-1,6-bisphosphate from glyceraldehyde-3-phosphate and DHAP. But, glucose may still be released through the breakdown of glycogen. Although, it cannot be synthesized from gluconeogenesis, resulting in severe hypoglycaemia.

[edit] Presentation

If fructose is ingested, other symptoms such as vomiting, hypoglycemia, jaundice, hemorrhage, hepatomegaly, hyperuricemia and eventually kidney failure will follow.

[edit] Treatment

Treatment is with a fructose free diet, which if adhered to, is concordant with a good prognosis. ^[1]

Fructose and sucrose eliminated from diet. ^[2]

[edit] Related conditions

Hereditary fructose intolerance should not be confused with fructose malabsorption. The latter is the same as dietary fructose intolerance (DFI), a deficiency of fructose transporter enzyme in the enterocytes, which leads to abdominal bloating, diarrhea and/or constipation.

[edit] See also

• Inborn error of metabolism

[edit] References

1. ^ -389021656 at GPnotebook
2. ^ /END101 at FPnotebook

[edit] External links

• Boston University HFI Lab
• http://www.uihealthcare.com/topics/medicaldepartments/foodandnutrition/dfi/whatisdfi.html
• Food-Info.net Fructose Intolerance (with list of acceptable and non-acceptable carbohydrates)
• [1]
• HFI-Info Discussion Board

v • d • e Inborn error of carbohydrate metabolism (including glycogen storage diseases) (E73-74, 271) Disaccharide catabolism Lactose intolerance - Sucrose intolerance Monosaccharide catabolism fructose: Essential fructosuria - Fructose intolerance galactose/galactosemia : Galactokinase deficiency - Galactose-1-phosphate uridylyltransferase galactosemia - Galactose epimerase deficiency Monosaccharide transport Glucose-galactose malabsorption - Inborn errors of renal tubular transport (Renal glycosuria) Glycolysis GSD type VII, Tarui's, phosphofructokinase - Triosephosphate isomerase deficiency - Pyruvate kinase deficiency Pyruvate catabolism PDHA - Fumarase deficiency Gluconeogenesis PCD - Fructose bisphosphatase deficiency - GSD type I, von Gierke, glucose 6-phosphatase Glycogenesis GSD type 0, glycogen synthase - GSD type IV, Andersen's, branching Glycogenolysis GSD type II, Pompe's, glucosidase - GSD type III, Cori's, debranching - GSD type V, McArdle, glycogen phosphorylase/GSD type VI, Hers', glycogen phosphorylase - GSD type I, von Gierke, glucose 6-phosphatas Pentose phosphate pathway Glucose-6-phosphate dehydrogenase deficiency - Pentosuria Other Hyperoxaluria see also glycolysis enzymes, pentose phosphate pathway enzymes, fructose and galactose metabolism enzymes