Recurrent acidosis with hypoglycemia in an infant: fructose-1,6-diphosphatase deficiency

A seven months old infant presented with recurrent episodes of acidosis and hypoglycemia triggered by fasting and febrile infections. The diagnosis of fructose-1,6-diphosphatase deficiency was made by demonstrating the enzyme deficiency in a liver biopsy specimen. Fructose-1,6-diphosphatase is a key enzyme of gluconeogenesis. Fructose-1,6-diphosphatase deficiency results in hypoglycemia and lactic acidosis during episodes of fasting. Diagnosis is made preferably by liver biopsy. Treatment includes elimination of fructose and sucrose from the diet and avoidance of fasting. Acute attacks are treated by intravenous infusion of glucose and bicarbonate if necessary.     

Hypoglycemia and hyperlactacidemia in relation with a new case of fructose-1,6-diphosphatase deficiency. Determination of enzymatic activity in leukocytes

A 11.5 month-old girl with recurrent episodes of hypoglycemia and lactic acidosis was identified as having fructose-1,6-diphosphatase deficiency. The diagnosis may be realised with a simple way by an oral fructose tolerance test and the activity dosage of this enzyme in white blood cells. The fructose and sucrose-free diet and avoidance of prolonged fasting resulted in a decrease of hepatomegaly and normal values of lactate between the episodes.     

Fructose 1,6-diphosphatase deficiency in 2 sisters]

The discovery of a fructose-1,6-diphosphatase deficiency in two sisters leads to the discussion of the various loading tests which are required for the diagnosis. The diagnosis may be discussed clinically with type I glycogenosis, and biologically with hereditary fructose intolerance. The specific characteristics of these disorders are analyzed as well as the problem of fructose induced hypoglucosemia. The failure of the treatment with folic acid in one of the cases leads to emphasize the suppression of prolonged fast in order to avoid acute accidents.     

Gluconeogenic key enzymes in normal and intrauterine growth-retarded newborn rats.

Intrauterine growth retardation was induced in rats by ligation of the artery of one of both uterine horns. Activities of pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1,6-diphosphatase and glucose-6-phosphatase in liver were measured at 0, 1, 3 and 6 h after delivery in newborn rats from normal and sham-operated litters, and from ligated and contralateral uterine horns. Lower activities of fructose-1,6-diphosphatase were found in small-for-gestational-age animals in comparison with animals from contralateral horns. When small-for-gestational-age animals were compared with animals from sham litters (which could be regarded as more satisfactory controls), the activities of two other gluconeogenic enzymes (pyruvate carboxylase and glucose-6-phosphatase) appeared to be lower as well. It is concluded that a delay in the development of these gluconeogenic enzymes could play a role in neonatal hypoglycemia in small-for-gestational-age rats.     

Perinatal development of glucoeneogenic enzymes in rabbit liver.

Activities of the 4 hepatic gluconeogenic enzymes: glucose-6-phosphatase, fructose-1,6-diphosphatase, pyruvate carboxylase, particulate and cytosolic phosphoenolpyruvate carboxykinase (PEPCK) have been measured in fetal rabbits (22, 25, 28, 30 and 31 days of gestation) and in fasted or suckling newborns (1 and 2 days after birth). Between days 25 and 31 of gestation, fructose 1,6-diphosphatase and particulate PEPCK activities represent 50% of adult (pregnant female) activities, while pyruvate carboxylase is present at adult values during the same period. Glucose-6-phosphatase is low and cytosolic PEPCK absent in fetal liver until 30 days of gestation and increase significantly during the day preceding birth. Al the enzymes show a further increase after birth independently of the nutritional status of the animals (starved or suckling).     

Congenital fructose 1,6 diphosphatase deficiency. Description of a case

In describing one case of congenital fructose 1,6-diphosphatase deficiency the Authors review the several clinical conditions giving problems of differential diagnosis. For certain diagnosis they underline the importance of liver biopsy, to dose the deficient enzyme directly in the liver tissue.     

Aldolase activities of the small intestinal mucosa in malabsorption states and hereditary fructose intolerance

Determination of aldolase activity in intestinal biopsy material offers a diagnostic alternative to liver biopsy in hereditary fructose intolerance (HFI). This diagnostic method could be validated by analysis of intestinal biopsies from eight patients with HFI. With the substrate fructose-1-phosphate (fru-1-p) we found 0.3±0.3 (x±SD) U/g of protein, with the substrate fructose-1,6-diphosphate (fru-1,6-p) 3.8±2.7 U/g of protein were measured. These results differ clearly from control activities (substrate = fru-1-p: 7.4±1.9 U/g of protein; substrate=fru-1,6-p: 13.9±4.3 U/g of protein). As the performance of the intestinal biopsy—in contrast to the liver biopsy—is virtually free of complications, it is recommended as the diagnostic method of choice in this disease.Aldolase activities were also determined in 40 intestinal biopsies from children with different malabsorption states: celiac disease (n=13), cow's milk protein intolerance (n=9), postinfectious syndrome (n=10), giardiasis (n=8). The activities differed clearly from our results in hereditary fructose intolerance. In celiac disease, cow's milk protein intolerance and postinfectious syndrome characteristic activity patterns were obtained: activities with fru-1,6-p were increased (celiac disease 17.2±5.7 U/g of protein; cow's milk protein intolerance 19.5±7.0 U/g of protein) or in the normal range (postinfectious syndrome 14.0±3.1 U/g or protein); activities with fru-1-p were decreased (celiac disease 2.3±1.0 U/g of protein; cow's milk protein intolerance 3.4±1.3 U/g of protein; postinfectious syndrome 5.0±0.8 U/g of protein). These results are discussed on the basis of aldolase isoenzyme distribution in the small intestinal mucosa.Herrn Prof. Dr. O. Hövels zum 60. Geburtstag gewidmetDiese Arbeit enthält sämtliche wesentlichen Teile der Doktorarbeit von Hanspeter Streb an der Universität Frankfurt     

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.     

Fructose-1,6-diphosphatase and glucose-6-phosphatase in newborn rats with intrauterine growth retardation.

The activities of two gluconeogenic enzymes, glucose-6-phosphatase and fructose-1,6-diphosphatase were examined in the normal and intrauterine growth retarded (IUGR) rat during the first 5 days of life. The fructose-1,6-diphosphatase activity, 1.54 +/- 0.10 mumol/min/g liver (means +/- SEM) in control and 1.47 +/- 0.20 in the IUGR rats, increased in both groups on days 2--4 but remained significantly lower in the IUGR rats through day 4 (4.53 +/- 0.6 mumol/min/g liver in control and 3.09 +/- 0.22 mumul/min/g liver in the IUGR rats, P less than 0.01). The glucose-6-phosphatase activity increased similarly in both groups. The weight of the IUGR rats remained lower through the third postnatal day (6.47 +/- 0.42 compared to 8.64 +/- 0.27 g in control rats). Blood glucose concentrations at birth were 117 +/- 11 mg/dl in control rats and 73 +/- 11 mg/dl in the IUGR rats (P less than 0.01). Although the glucose concentrations increased in both groups on days 2--4, the IUGR rats maintained relatively lower levels (P less than 0.01). The results indicate that IUGR fetal rats do not have augmented gluconeogenesis in spite of hypoglycemia. In addition, effective gluconeogenesis in the neonatal period appears to be delayed.     

Fructose-induced hyperuricemia: observations in normal children and in patients with hereditary fructose intolerance and galactosemia.

After the infusion of fructose, 0.25 g/kg body wt, the mean peak plasma uric acid level was 5.4 +/- 0.7 (SEM) mg/100 ml in six normal children and was not significantly increased compared with that of the mean basal value of 4.1 +/- 0.5 mg/100 ml. The mean blood inorganic phosphate (Pi) levels were significantly less than the mean fasting value after fructose. Blood glucose, lactic acid, and fructose levels were significantly increased after fructose, but serum magnesium levels did not change. In two patients with hereditary fructose intolerance (HFI) the peak blood uric acid levels were 12.1 and 7.6 mg/100 ml, respectively, after fructose. In both patients the blood glucose concentrations decreased 69 and 26 mg/100 ml below the fasting levels after fructose. The serum Pi level decreased 2.3 and 1.2 mg/100 ml below fasting values, decrements greater than the mean decrement in serum Pi of 0.8 +/- 0.2 mg/100 ml which occurred in six normal children. The mean uric acid excretion, expressed as milligrams per mg urinary creatinine, was 0.6 +/- 0.1 (SEM) before fructose in the normal children and increased significantly to 1.0 +/- mg/mg creatinine after fructose. In two patients with HFI the uric acid excretion increased four- to fivefold after fructose administration; the increased uric acid excretion in HFI exceeded that of normal children. In three patients with galactosemia, increases in blood uric acid levels after galactose ingestion were similar to those in normal children after fructose, but less than those in patients with HFI after fructose. The serum Pi levels decreased less in galactosemic patients after galactose administration than in patients with HFI after fructose infusion. These studies support the hypothesis that fructose-induced hyperuricemia results from degradation of adenosine monophosphate. This effect appears to be specific for fructose. The lack of hyperruricemia in galactosemia patients after galactose ingestion may be explained by the observation that galactose is phosphorylated more slowly than fructose.     

Increased concentrations of HbAlab in hereditary fructose intolerance and galactosemia

In patients with diabetes mellitus nonenzymatic glycosylation of hemo-globin is a result of increased blood glucose concentrations. In analogy glycosylated hemo-globin fractions were determined in 23 patients with hereditary fructose intolerance (HFI) and 8 patients with galactosemia (G) by means of hemoglobin chromatography on a column packed with Bio-Rex 70 resin. The concentrations were compared to those of 14 control patients and 43 patients with type 1 diabetes mellitus. Compared to controls, in HFI- and G-patients HbAlab was significantly increased. In contrast diabetic patients presented with a marked and significant increase of the HbAlc fraction. When purified hemoglobin was incubated with different monosaccharides respectively monosaccharide phosphates, an increase of HbAlab resulted mainly after galactose and fructose-1-phosphate. The determination of HbAlab in patients with HFI and G is considered a possible means of metabolic control.     

Hereditary fructose intolerance (HFI) as cause of isolated gamma GT rise in a 5-year old boy with hepatomegaly

The diagnosis of HFI is easily missed during childhood. It should be suspected in children presenting with hepatomegaly and an isolated increase in GGT. A carefully taken nutritional history forms the basis of the diagnosis of HFI which can be confirmed by molecular analysis with a sensitivity of > 95%. I.v. fructose tolerance tests and liver biopsies often can be omitted.     

Fructose-1,6-diphosphatase deficiency. Clinical aspects and diagnosis based on a case report

In a 2-year-old boy the enzyme defect of fructose-1,6-diphosphatase deficiency could be demonstrated in liver tissue, jejunal mucosa and leukocytes. During the neonatal period the boy had suffered from transient metabolic acidosis and hypoglycemia. At the age of 2 years, during a febrile infection, he developed a hyperkinetic-hypotonic syndrome, which disappeared by fructose-free diet and avoidance of prolonged periods of fasting.     

STUDIES ON A PATIENT WITH IN VIVO EVIDENCE OF TYPE I GLYCOGENOSIS AND NORMAL ENZYME ACTIVITIES IN VITRO

ABSTRACT. Biochemical and clinical studies on a patient with hepatic glycogen storage disease are reported. The patient showed many of the clinical and biochemical features of type I glycogenosis (glucose-6-phosphatase deficiency), but had normal activities of the following enzymes in liver tissue: glucose-6-phosphatase (EC3.1.3.9); amylo-1,6-glucosidase (EC3.2.1.33); glycogen phosphorylase (EC2.4.1.1); fructose-1,6-diphosphatase (EC3.1.3.11). The urinary excretion of 2-oxoglutaric acid was greatly increased in this patient and in a case of enzymologically proven type I glycogenosis. Abnormal 2-oxoglutaric aciduria has not been previously reported in the glycogen storage diseases. The results are discussed in relation to the possible nature of the underlying biochemical defect in patients of this type.     

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.     

Studies on a patient with in vivo evidence of type I glycogenosis and normal enzyme activities in vitro.

Biochemical and clinical studies on a patient with hepatic glycogen storage disease are reported. The patient showed many of the clinical and biochemical features of type I glycogenosis (glucose-6-phosphatase deficiency), but had normal activities of the following enzymes in liver tissue: glucose-6-phosphatase (EC3.1.3.9); amylo-1,6-glucosidase (EC3.2.1.33); glycogen phosphorylase (EC2.4.1.1); fructose-1,6-diphosphatase (EC3.1.3.11). The urinary excretion of 2-oxoglutaric acid was greatly increased in this patient and in a case of enzymologically proven type I glycogenosis. Abnormal 2-oxoglutaric aciduria has not been previously reported in the glycogen storage diseases. The results are discussed in relation to the possible nature of the underlying biochemical defect in patients of this type.     

Biochemical and clinical observations in four patients with fructose-1,6-diphosphatase deficiency

Three boys and one girl suffering from inherited fructose-1,6-diphosphatase (FDPase) deficiency are reported. All four patients had less than 25% residual hepatic FDPase activity. While in two out of three patients the enzyme deficiency was also expressed in leucocytes, one patient had a normal enzyme activity. Remarkably, three patients had pronounced neonatal hyperbilirubinaemia requiring exchange transfusion.     

Metabolic disorders presenting as liver disease

A wide range of inherited metabolic disorders lead to biochemical disturbances within the liver. A number of disorders of energy metabolism present as hepatomegaly with hypoglycaemia e.g. glycogen storage diseases or with hypoketotic hypoglycaemia e.g. disorders of fat oxidation. Other defects of carbohydrate metabolism also present with hypoglycaemia and liver disease either in neonates e.g. galactosaemia and fructose-1,6-bisphosphatase deficiency or at weaning i.e. hereditary fructose intolerance. Mitochondrial respiratory chain defects frequently present in neonates/infants as liver disease but often there is other (multi)-organ involvement and persistent lactic acidaemia. Many disorders of peroxisomal and lysosomal metabolism cause a spectrum of liver dysfunction. Urea cycle disorders manifest as hyperammonaemia often presenting acutely in neonates but also in older children and adults. Other causes of liver disease include disorders of copper, bile acid and bilirubin metabolism. Definitive diagnosis requires specialist expertise, however once clinical liver disease is apparent, most disorders are associated with characteristic findings on routine laboratory testing that should raise the suspicion of metabolic disease.     

Hereditary fructose intolerance: A comprehensive review

Hereditary fructose intolerance (HFI) is a rare autosomal recessive inherited disorder that occurs due to the mutation of enzyme aldolase B located on chromosome 9q22.3. A fructose load leads to the rapid accumulation of fructose 1-phosphate and manifests with its downstream effects. Most commonly children are affected with gastrointestinal symptoms, feeding issues, aversion to sweets and hypoglycemia. Liver manifestations include an asymptomatic increase of transaminases, steatohepatitis and rarely liver failure. Renal involvement usually occurs in the form of proximal renal tubular acidosis and may lead to chronic renal insufficiency. For confirmation, a genetic test is favored over the measurement of aldolase B activity in the liver biopsy specimen. The crux of HFI management lies in the absolute avoidance of foods containing fructose, sucrose, and sorbitol (FSS). There are many dilemmas regarding tolerance, dietary restriction and occurrence of steatohepatitis. Patients with HFI who adhere strictly to FSS free diet have an excellent prognosis with a normal lifespan. This review attempts to increase awareness and provide a comprehensive review of this rare but treatable disorder.     

Neonatal lactic acidosis and hypoglycemia due to a congenital hepatic fructose-1,6-diphosphatase deficiency]

Famialial defect of hepatic fructose-1,6-diphosphatase. Diagnosis was suspected in a male newborn since a brother was also concerned by the disease. The disease may be therefore diagnosed early, when the onset is neonatal. In the neonatal distress syndromes due to hereditery disorders of metabolism, a semiologic field may be isolated in which symptoms begin after an interval of short duration with hypoglycemia, hepatomegaly, lactic acidosis and ketosis ("enlarged liver hypoglycemia"). This possibility leads first to a symptomatic treatment of hypoglycemia and acidoketosis, then to the feeding with human milk and simple functional tests for the diagnostic approach.