Fructosuria

The hexokinase procedure can be carried out with the use of reagents which are supplied from various companies. From Table I it can be seen that these reagents vary in their specificity depending whether or not they have removed fructose hexokinase. However, as long as one is dealing with serum and not with a fructosuria, the procedure is specific. 

In those patients who survive more than a few weeks, the effects of renal tubular dysfunction become more severe. Acidosis and hypo-phosphatemic rickets are prominent features. The urine is alkaline and gives a strong Rothera reaction. However, the ability to concentrate the urine is never lost and there is neither polydipsia nor polyuria. Aminoaciduria, hydroxyphenyluria, glucosuria, fructosuria, and proteinuria continue. The liver remains large and cirrhotic. Death finally occurs in liver failure, sometimes after several years. There is evidence that some children recover with no residual signs other than a large firm liver. 

Essential fructosuria is a benign, asymptomatic condition arising from deficiency of the enzyme fructokinase that causes a portion of fructose to be excreted in the urine. 

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. 

Fructokinase is deficient in essential fructosuria therefore, fructose can-s not be metabolized as rapidly as it normally would. Blood fructose levels... 

C. Fructose derived from the table sugar (sucrose) would not be converted to fructose 1-phosphate, so it accumulates in the blood and is excreted in the urine, producing a benign fructosuria. 

Fructose may appear in the urine after eating fruits, honey, and syrups, but has no significance in these circumstances. Three disorders of fructose metabolism, inherited as autosomal recessive traits, produce fructosuria. 

Essential fructosuria A rare, benign genetic condition in which fructose spills over to the urine because the Uver, kidney, and intestine lack the enzyme fructokinase. 

The enzyme presumed to be deficient in benign fructosuria is the fruc-tokinase. The reasoning is based on the fact that there is no demonstrable utilization, no drop in serum phosphorus when fructose is administered,... 

L8. Levine, R., and Taubenhaus, M., Clinical conference on metabolism problems. Essential fructosuria. Metabolism Clin, and Exptl. 3, 82-87 (1954). 

There are two genetic diseases associated with fructose metabolism. One is fructosuria, in which the liver enzyme, fructokinase, is missing. Thus, fructose is not metabolized but, instead, accumulates in the blood and is passed into... 

Essential fructosuria is a rare and benign genetic disorder caused by a deficiency of the enzyme fructok-inase. Why is this disease benign, when a deficiency of aldolase B (hereditary fructose intolerance) can be fatal Could Candice Sucher have essential fructosuria ... 

In essential fructosuria, fructose cannot be converted to fructose 1-phosphate. This condition is benign because no toxic metabolites of fructose accumulate in the liver, and the patient remains nearly asymptomatic. Some of the ingested fructose is slowly phosphorylated by hexokinase in nonhepatic tissues and metabolized by glycolysis, and some appears in the urine. There is no renal threshold for fructose the appearance of fructose in the urine (fructosuria) does not require a high fructose concentration in the blood. 

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