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1/18. fructose-1,6-diphosphatase deficiency and glyceroluria: one possible etiology for GIS.

    Fructose-1,6-diphosphatase (FDPase) deficiency is characterized by episodes of lactic acidemia, hypoglycemia, and ketonuria. liver biopsy and subsequent enzyme analysis most reliably make the diagnosis. review of the literature reveals 85 cases. glycerol intolerance syndrome (GIS) is less well defined. There are only a handful of cases reported. We describe a patient with FDPase deficiency and significant glyceroluria and propose that GIS may be caused by partial deficiency of FDPase. ( info)

2/18. Fructose and glucagon loading in siblings with fructose-1,6-diphosphatase deficiency in fed state.

    Hypoglycaemia induced by fructose administration is one of the diagnostic clues to fructose-1,6-diphosphatase (FDPase) deficiency (McKusick 229700). However, the pathological mechanism of this reactive hypoglycaemia is not fully known. This paper describes two siblings with FDPase deficiency, diagnosed enzymatically in leukocytes, who failed to correct reactive hypoglycaemia after glucagon administration even in the fed state, supporting a possibility that disturbed hepatic phosphorylase activity may be a main cause of reactive hypoglycaemia. ( info)

3/18. fructose-1,6-diphosphatase deficiency: a rare cause of prolonged prothrombin time.

    A 20-year-old woman presented with severe life-threatening metabolic acidosis and hypoglycemia. In addition, her blood tests revealed elevated hepatic enzymes and a prolonged prothrombin time, with a reduction in factor vii activity. After treatment with a glucose and bicarbonate-containing intravenous infusion, there was a dramatic clinical improvement and normalization of the prothrombin time within 2 days. The patient was found to have fructose-1,6-diphosphatase deficiency, a rare metabolic disorder which has not been described previously as causing coagulation defects. ( info)

4/18. Lactic acidosis in childhood.

    Children with chronic metabolic acidosis should be investigated to determine the presence of an organic acid, especially when the plasma electrolyte profile shows a deficiency of anion. One of the organic acids that should be looked for in such a patient is lactic acid. Lactic acidosis due to tissue hypoxia is a well-known phenomenon (e.g., in shock and cardiopulmonary disease) and has not been discussed in this essay; nor has lactic acidosis due to exogenous causes like infusion of fructose or sorbitol, or admiministration of phenformin. Chronic lactic acidosis in infancy is a rare condition. It may be associated with glycogen storage disease Type 1, fructose diphosphatase deficiency, methylmalonic acidemia, propionic acidemia, pyruvate carboxylase or dehydrogenase deficiency and Leigh's subacute necrotizing encephalomyelopathy (SNE). Some patients with chronic lactic acidosis do not have nay of these diseases and comprise an "idiopathic" group. This is a heterogeneous group, probably having several different causes for the metabolic error. In Leigh's SNE, a metabolic block in the formation of thiamine triphosphate in brain has been demonstrated and has been attributed to the presence of an inhibitor of thiamine pyrophosphate-adenosine triphosphate (TPP-ATP) phosphoryl transferase in body fluids. The inhibitor has also been encountered in cases of intermittent cerebellar ataxia and of primary hypoventilation (Ondine's curse), which may represent variants of Leigh's disease. Increased blood levels of lactate, pyruvate and alanine frequently are encountered in SNE, but it still is not clear whether they are due to a primary or secondary disturbance in the catabolism of pyruvate. Disturbed lactate and pyruvate metabolism has also been encountered in isolated cases of mental retardation and growth failure, in mitochondrial myopathies and in polyneuropathies, and may be expected to occur in Wernicke's encephalopathy. Finally, it has been noted in malignancy and in association with other rare metabolic disorders. ( info)

5/18. fructose-1,6-diphosphatase deficiency.

    A girl aged 3 years and 11 months, with recurrent episodes of unexplained metabolic acidosis, hepatomegaly, and fasting hypoglycemia unresponsive to glucagon, showed profound falls in blood glucose levels in response to oral fructose and glycerol challenge. in vitro analysis of her hepatic glycolytic and gluconeogenic enzymes demonstrated absent fructose-1,6-diphosphatase activity. A therapeutic trial of orally given folic acid, 30 mg daily, did not improve her tolerance for fructose and glycerol. Over the next two years she showed improvement in tolerance to fasting, and to fructose and glycerol loading on dietary management. ( info)

6/18. Characterization of human fructose-1,6-bisphosphatase in control and deficient tissues.

    The regulatory properties of human liver and muscle fructose-1,6-bisphosphatases (FBPase) have been studied in control tissues obtained at autopsy and in tissues from a neonate with FBPase deficiency who died as a result of an overwhelming acidosis. Evidence is presented which suggests that the alkaline isoenzyme of FBPase, which is widely regarded as a laboratory artefact, may have an important role in vivo in the regulation and control of glycolysis and gluconeogenesis. FBPase exhibits the hysteretic and dissociative properties associated with regulatory enzymes, and many of the factors which effect FBPase have inverse effects on phosphofructokinase activity, thus providing an integrated regulatory cycle for the control of the direction and rate of flux through the glycolytic pathway. ( info)

7/18. Combined deficiency of glucose-6-phosphatase and fructose-1, 6-diphosphatase. Studies of glucagon secretion and fuel utilization.

    An adult woman with hypoglycemia, hyperlactatemia, hyperuricemia, hypertriglyceridemia, hyperketonemia and inability to make new glucose from galactose, fructose, glycerol and alanine was found to have no hepatic glucose-6-phosphatase and deficient fructose-1,6-diphosphatase. Nonautonomous hyperglucagonemia was demonstrated and shown to contribute to the hyperlactatemia and hyperketonemia. A paradoxic hyperlactatemic response to glucose and galactose was observed. Studies of substrate utilization showed prompt adaptation to changes in dietary supply of energy which probably accounted for her never having experienced symptoms of hypoglycemia. ( info)

8/18. Deficiency of glucose-6-phosphate dehydrogenase found in a case of hepatic fructose-1,6-diphosphatase deficiency.

    The first case of fructose-1,6-diphosphatase (FDPase) deficiency in japan showed a decreased activity of glucose-6-phosphate dehydrogenase (G6PD) in the liver, white, and red blood cells. In the enzymatic study of G6PD which was partially purified from red cells, the following characteristics were observed in the enzyme of the patient. 1) The G6PD activity of the patient was reduced to 17% of normal, but no evidence of a hemolytic episode was found in his past and family history. 2) In the investigation of G6PD of the patient, no abnormalities were observed in its enzymatic parameters such as electrophoretic mobility, Km for G6P and nadp, Ki for NADPH, the utilization of 2-deoxy G6P and deamino nadp, heat-stability, and pH curves. 3) The dissociation constants of red blood cell G6PD for nadp and NADPH, which were obtained from the investigations on the reactivation of cold-inactivated G6PD at 37 degrees C, were about 3 times higher in the patient as compared to the values of the normal controls. Based on these findings, it might be concluded that the G6PD deficiency found in the red blood cells of this case of a FDPase deficiency is a unique variant, which could not be characterized by using only the method recommended by a world health organization (WHO) scientific group. Considering that the abnormality observed in the G6PD of this patient was a decrease in the affinity of the enzyme for its coenzymes, the dissociation constants for the coenzymes in reactivation process might be another important kinetic parameter in characterizing the G6PD deficiency. ( info)

9/18. Severe acidosis in a neonate with pulmonary valve stenosis: a possible stress inducer of a fatal syndrome of fructose-1, 6-biphosphatase and aldolase deficiency.

    A neonate is described whose clinical condition rapidly and irreversibly deteriorated on day two. He developed a profound acidosis, hypoglycaemia and a shock-like syndrome. The infant was centrally cyanosed and had a systolic murmur from a moderately severe pulmonary valve stenosis and a small atrial septal defect. The overwhelming acidosis was inconsistent with the severity of the congenital heart defects and as no infection was found a metabolic cause was sought. liver tissue obtained at autopsy shortly after death on day four, showed deficiencies of fructose-1, 6-biphosphatase and aldolase. ( info)

10/18. fructose-1,6-diphosphatase deficiency: glycerol excretion during fasting test.

    A Turkish boy had suffered since the age of 10 months from recurrent attacks of severe metabolic acidosis and hypoglycaemia precipitated by moderate respiratory tract infections. A liver biopsy showed lack of fructose 1,6-diphosphatase and absence of phosphorylase. The patient died in shock following fructose ingestion. Upon fasting, acidosis with increased lactate and glycerol excretion was found. Findings indicate that, in this inherited disorder of gluconeogenesis, lactic acidosis combined with increased glycerol excretion upon fasting are of diagnostic importance. ( info)
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