1 Isaac Albert Research Institute of the Jewish Chronic Disease Hospital, Brooklyn 3, New York
1. Children with Tay-Sachs' disease and patients with hereditary fructose intolerance both have severely depressed levels of serum fructose-1-phosphate aldolase.
2. Administration of fructose to three patients with Tay-Sachs' disease did not precipitate the drop in serum glucose and inorganic phosphorus and the rise in serum magnesium that is characteristic of the response to exogenous fructose of patients with hereditary fructose intolerance.
3. The normal tolerance to exogenous fructose displayed by patients with Tay-Sachs' disease is consistent with the findings that their hepatic fructose-1-phosphate aldolase is reduced to only about 60% of normal, in contrast to the virtual absence of this enzyme in cases of hereditary fructose intolerance.
4. It is suggested that even though the serum fructose-1-phosphate aldolase is low in Tay-Sachs' disease, the defect in cerebral ganglioside metabolism may involve galactose rather than fructose.