Fructose intolerance

D-Fructose Fruit juices. Honey. Hydrolysis of cane sugar and of inulin (from the Jerusalem artichoke). Can be changed to glucose in the liver and so used in the body. Hereditary fructose intolerance leads to fructose accumulation and hypoglycemia. 

Deficiency of aldolase B, although this isozyme is not expressed in red blood cells, is responsible for hereditary fructose intolerance, an autosomal recessive dis-... 

T16. Tolan, D. R Molecular basis of hereditary fructose intolerance Mutations and polymorphisms in the human aldolase B gene. Hum. Mutat. 6,210-218 (1995). 

Fructose intolerance is a condition showing a number of close similarities to galactosemia (F3, W5). It has been shown that, in fructose intolerance, fructose-l-phosphate accumulates and inhibits a number of enzymes. Marked hypoglucosemia follows ingestion of fructose, but insulin is almost certainly not involved (FI, P10). 

The concentration of free Pj decreases as it may in galactosemia, hereditary fructose intolerance, and glucose 6-phosphatase deficiency. 

Hereditary fructose intolerance is due to aldolase B deficiency and is often diagnosed when babies are switched from formula or mother s milk to a diet containing fructose-based sweetening, such as sucrose or honey. 

Fructose intolerance causes vomiting, severe hypoglycemia, and kidney and liver damage that may lead to organ failure and death. 

Contraindications Intestinal obstruction, GI tract not anatomically intact patients at risk of hemorrhage or GI perforation, if use would increase risk and severity of aspiration not effective for cyanide, mineral acids, caustic alkalis, organic solvents, iron, ethanol, methanol poisoning, lithium do not use charcoal with sorbitol in patients with fructose intolerance, hypersensitivity to charcoal or any component of the formulation... 

Contraindications Symptoms of appendicitis or inflamed bowel, hereditary fructose intolerance, hypersensitivity to any component of the formulation... 

Fructose intolerance includes symptoms of fainting, swelling efface, arms and legs, unusual bleeding, vomiting, weight loss, and yellow eyes and skin. 

Life-threatening adverse reactions with IV sorbitol infusions have been reported in patients with fructose intolerance. 

Fructose 1-phosphate aldolase B Hereditary fructose intolerance, vomiting, lethargy, failure to thrive, hepatic failure good prognosis with early diagnosis and fructose restriction... 

Hereditary fructose intolerance (HFI), caused by the deficiency of fructaldolase, and fructose- 1,6-bisphosphatase deficiency. 

Fructose-bisphosphate aldolase, which also acts on fructose-1-phosphate, is the enzyme deficient in hereditary fructose intolerance (HFI, MIM 229 600). 

Table 4.6.7 Pathological values of fructose-l-phosphate and fructose-1,6-bisphosphate in patients with hereditary fructose intolerance (HFI) [36]...

Cause and treatment of hereditary fructose intolerance A deficiency of fructokinase causes a benign condition, but a deficiency of aldolase B causes hereditary fructose intolerance, in which severe hypoglycemia and liver damage can lead to death if the amount of fructose (and, therefore, sucrose) in the diet are not severely limited. 

These enzymes have been found in all plant and animal tissues examined and are absent only from a few specialized bacteria. Three closely related isoenzymes are found in vertebrates.185 186 The much studied rabbit muscle aldolase A is a 158-kDa protein tetramer of identical peptide chains.186 187 Aldolase B, which is lacking in hereditary fructose intolerance, predominates in liver and isoenzyme C in brain.185... 

Carbohydrate abnormalities, such as renal glycosuria (a transport defect), pentosuria (enzyme deficiency, xylitol dehydrogenase I. lactase deficiencies, fructose intolerance, galactosemia, galacloki-nase deficiency, oxalosis, and several glycogenoses (von Gierke s, Forbes . Andersen s, Hers s. and Tarui s diseases). 

DHAP is a glycolysis intermediate, whereas glyceraldehyde must be reduced by a mitochondrial enzyme, glyceraldehyde dehydrogenase, to glycerol, which is then subject to action by glycerol kinase in the liver. The aldolase seems to be the principal pathway of metabolizing fructose and depends on the initial phosphorylation step catalyzed by fructokinase, which produces fructose-l-phosphate. Fructokinase is defective in an inherited disorder, essential fructosuria. Fructose-l-phosphate aldolase is deficient in the hereditary disorder fructose intolerance. 

Phenylketonuria Alcaptonuria Hyperammonemia I Hyperammonemia II McArdle s syndrome Hypophosphatasia Congenital lactase deficiency Hereditary fructose intolerance Gout... 

Deficiency in fructose metabolism, as in essential fme-tosuria, may be perfectly benign, for one is not interrupting the main line of the glycolytic chain. However, there is one condition, hereditary fructose intolerance, which does cause significant problems. 

Wilson s disease, haemochromatosis, galactosaemia, glycogenosis type IV, ai-antitrypsin deficiency, tyrosin-aemia, idiopathic neonatal hepatitis, Niemann-Pick disease, Gaucher s disease, fructose intolerance, defective urea cycle, etc. 

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