[Diagnostic procedures in hereditary fructose intolerance (author's transl)].

In order to diagnose hereditary fructose intolerance up to now, there were only the dangerous fructose-load and the biochemical evidence of this metabolic defect from biopsies of liver, intestine or kidney. Since there are no screening tests nor tests for heterocygote carriers or prenatal diagnostic procedures, we tested a simple method to determine serum activities of the two enzymes concerned in this defect (fructose-1-phosphate aldolase, fructose-1,6-diphosphate aldolase). Even in completely healthy children we could measure both activities in a good range. Children with known liver lesion caused other than HFI had significantly increased activities of both enzymes. In 4 cases with HFI we could not measure any activity of fructose-1-phosphate aldolase and a decreased activity of fructose-1,6-di-phosphate aldolase in serum, despite an apparently damaged liver. We propose to define those two serum activities in any case of an obscure liver lesion, frequent vomiting and postprandial hypoglycemia in early childhood, in order to exclude HFI or to demonstrate its possible presence.