Hereditary fructose intolerance, lack

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... 

This rare and harmless defect is due to a lack of fructokinase. Hereditary Fructose Intolerance... 

Intoxication disorders include urea cycle disorders, organic acidurias, aminoacidopathies, fatty acid oxidation disorders, and carbohydrate disorders such as galactosemia or hereditary fructose intolerance. In these disorders, a partial or complete lack of enzymatic activity causes the accumulation of substances proximal to the metabolic block in tissues and body fluids, where they act as toxins (Fig. 5.1). Treatment is based on limiting the substances that are the source of the toxic metabolites and introducing alternatives (e.g., drugs, procedures) that speed the elimination of those toxic metabolites. 

In contrast to hereditary fructose intolerance where lack of fructose-1-phosphate aldolase (Levin et al. 1963) in serum and liver is a prominent feature, liver fructose-1-phosphate aldolase activity in TSD is only reduced to approximately 60%, and fructose tolerance is not impaired in the latter disorder (Schneck et al. 1965), while in the former accumulation of fructose-1-phosphate and hypoglycemia... 

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