Kazuyasu Nakata

The First Case of Fructose-1,6-diphosphatase Deficiency in Japan

A case of fructose diphosphatase (FDPase) deficiency is reported. The patient was a 3-year old boy who had been noted to have frequent episodes of symptomatic hypoglycemia and hepatomegaly since 8 months of age. The metabolic state in the patient was studied with loading tests. He presented symptomatic hypoglycemia after oral administration of glycerol and fructose. Alanine (0.5 g/kg, p.0.) did not cause any significant change in blood glucose. Ketotic provocative test fdfilled the criteria of ketotic hypoglycemia with the exception of no acetonuria. During the episodes of symptomatic hypoglycemia, the plasma levels of lactate, pyruvate, and alanine and the ratio of lactate/pyruvate were markedly elevated. The decreased ketogenesis and high lactate/pyruvate ratio were closely similar to the findings obserbed in von Gierke’s disease. The biopsied specimen of his liver disclosed no activity of FDPase. The activities of other hepatic enzymes, glucose-6-phosphatase, F1 -P aldolase and FDP aldolase were all in normal range. However, it was found that glucose6-phosphate dehydrogenese activity was markedly decreased (about one fourth of the normal values), both in the liver and the red cells. The family history revealed that one of his two sisters died of hepatomegaly and hypoglycemia at 14 months of age. His parents, not consanguineous, are in good health. The activity of leukocyte FDPase was determined in the family members. It was significantly reduced in the patient and about 50% of the normal in his mother. His father and healthy sister showed normal leukocyte FDPase activity. Consequently, the mother seem to be a heterozygote; however, the mode of inheritance remains to be clarified. This report is considered to be the first of FDPase deficiency in Japan.

The study of Pulmonary Hypertension in Heart Diseases of Children

Considering the significance of the height of peak pressure (a) and dicrotic notch (c) of the main pulmonary artery, we regarded the main pulmonary artery as a single compression chamber, including both the left and the right main pulmonary branches, and we found that c/a in a congenital heart disease group with L-R shunt was larger than that in the control group. In order to find out the factors determining c/a, we injected intravenously phentolamineHC1 and observed its effect. Cia was higher in the QP/QS<P-group than in the QP/ QS 2 2-group The sympathetic vascular tonus took part largely in the QP/QS<2-group. We also found that the pre-loading value of cia was high in QP/QS22-group in spite of low reactivity to phentolamine-HC1. We think that it was caused primarily by the lowering of distensibility resulting from pulmonary dilatation.