| Popis: |
The mode of presentation and the clinical course in seven new cases of fructosaemia are described. Two main categories are recognized. The introduction of fructose (sucrose) into the diet, at under six months of age, results in vomiting, anorexia, failure to thrive and evidence of hepatorenal dysfunction, sometimes with hypoglycaemic convulsions, and a transient bleeding tendency. One patient presented with severe multiple renal tubular dysfunction, which returned to normal on exclusion of fructose from the diet. Two infants died in the neonatal period. When fructose is included in the diet at a later age the illness is less severe, even asymptomatic, or presents as spontaneous hypoglycaemia. None of the surviving patients is retarded mentally or physically. In all cases an oral dose of fructose caused a marked increase in blood fructose, a decrease in blood glucose and phosphate, and an increase in plasma magnesium. It is suggested that the hypoglycaemia is due to the inhibition of both gluconeogenesis and glycogenolysis, the former resulting from fructose-1:6-diphosphate aldolase deficiency, and depletion of adenosine triphosphate (ATP) and the latter from the intracellular fall of inorganic phosphate and ATP resulting from the enzyme block. Aldolase activities were measured in the liver of three of the seven patients and also in the jejunum of one. In all three there was a severe but variable deficiency in liver fructose-1-phosphate aldolase activity and a lesser, also variable deficiency in fructose-1:6-diphosphate aldolase activity. The jejunal aldolase activities in the one case were within normal limits. The variation of the liver enzyme activities in the three patients, and in twelve previously described, supports the suggestion that there may be more than one genotype. |
