[Carbohydrate intolerance as a danger in infusion therapy]

The following types of carbohydrate intolerance are discussed as a risk in infusion therapy: Hereditary fructose intolerance, fructose-1,6-biphosphatase deficiency, impairment of glucose utilization during the post-aggression syndrome and/or in latent or overt diabetes mellitus. Asking about symptoms of fructose intolerance has to be part of every routine anamnesis. Application of any kind of carbohydrate requires differential therapeutic considerations. Undiscovered fructose intolerance is more likely the younger the patient is, whereas the frequency of glucose intolerance increases with age. In unconscious patients without anamnesis, fructose or sorbitol should not be applied. Never should an attempt be made to compensate falling blood glucose levels under infusion therapy by application of fructose or sorbitol. As carbohydrate addition to routine fluid and electrolyte substitution xylitol in the specified low dosage is without risk in a diabetes-like metabolic condition as well as in fructose intolerance.

Sucrase deficiency in Greenland. Incidence and genetic aspects

The disaccharidase activities in small-intestinal surgical biopsy specimens from 97 Greenlanders were investigated. Five of the patients, or 5%, had sucrase deficiency. The diagnosis, sucrose malabsorption, was established by sucrose tolerance tests. In all parts of the world other than the arctic regions sucrase deficiency is a rare condition. The patients were divided into three separate groups in accordance with their sucrase activity. The middle group was considered to be heterozygote carriers of the sucrase-deficient gene. The number of people in the group corresponded to the theoretical number of heterozygotes in accordance with the Hardy-Weinberg equation, suggesting that sucrase deficiency is recessively inherited in a simple Mendelian fashion. Four of the five patients with sucrase deficiency had deficiency of lactase as well. The nutritional implications are discussed.

Autosomal recessive inherited phosphofructokinase deficiency in English springer spaniel dogs

Three families of English springer spaniel dogs with phosphofructokinase (PFK) deficiency causing haemolysis were studied. Four male dogs and one female dog with chronic haemolysis and haemolytic crises were found to have markedly reduced PFK activity in erythrocytes (8-20% of control English springer spaniels). PFK-deficient erythrocytes exhibited an extreme alkaline and sucrose lysis. The oxygen dissociation curve of erythrocyte suspensions was shifted to the left with a 50% saturation of haemoglobin at a partial oxygen pressure of 16-17 mmHg (normal 26-31 mmHg). Muscle wasting and mildly increased serum creatine phosphokinase activity were also noted. Six clinically normal first degree relatives of affected dogs had erythrocyte PFK activities that were 38-51% of controls. In these family members, there was an erythrocytosis and mild reticulocytosis probably due to a mildly enhanced haemoglobin-oxygen affinity but no increase in serum creatine phosphokinase. These studies confirm the familial nature of muscle-type PFK deficiency in English springer spaniels and support the conclusion that this animal model of the human glycogen storage disease type VII is inherited as an autosomal recessive trait.

Phosphoglycerate kinase: studies on normal and a mutant human enzyme

Phosphoglycerate kinase was purified from a number of tissues obtained at autopsy from a subject with the deficiency. Properties of the mutant enzyme were compared to those of PGK purified from tissue obtained from normal subjects. The purified enzyme from the propositus contained two components, a minor fraction (about 2-5%) which behaved similarly to the normal enzyme during the purification procedure, and a major fraction (greater than 95%) which could not be purified by the same procedure. The major fraction demonstrated a number of other properties which differed from the normal. These included a tendency to form aggregates, increased heat sensitivity and altered nucleotide substrate specificity. The smaller fraction appeared to have effectively identical properties to that of the normal enzyme. In keeping with its X-linked mode of inheritance, phosphoglycerate kinase from all normal tissues appeared to have identical kinetic properties, although evidence for minor variations, presumably due to post-translational modifications, was obtained.

Frequency of glucose-6-phosphate dehydrogenase, pyruvate kinase and hexokinase deficiency in the Saudi population

The frequencies of glucose-6-phosphate dehydrogenase (G-6-PD), pyruvate kinase (PK) and hexokinase (HK) deficiency were determined in different regions of Saudi Arabia. G-6-PD deficiency was found to range from 0.045 to 0.220 for the male and 0.020 to 0.125 for the female population. The highest frequencies were found to exist in the regions which are endemic to malarial parasite and have high frequencies of sickle cell and thalassaemia genes. Partial deficiencies of PK and HK were encountered in each region, however, no case of complete deficiency of these enzymes was identified. Further investigations are in progress to determine the clinical manifestations of enzyme deficiencies in the Saudi population.

Direct and maternal aspects of the risk of cataract with partial disorders of galactose metabolism

Partial deficiencies of the enzymes of galactose metabolism can be associated with cataract, both directly and through maternal effects during pregnancy on enzymatically normal children. However, the associations are modest, variable and not obviously expressing cause and effect. We have recorded ophthalmological and biochemical observations including oral galactose tolerance on families with established enzyme deficiencies and/or cataracts, including possible effects during pregnancy. With the partial disorders a simple relationship between the extent of biochemical abnormality and the risk of cataract is not apparent and the association may be substantially coincidental. Cataract is common, and the attractive possibility that expression is significantly due to heterozygous or lesser deficiency of the enzymes of galactose metabolism, amenable to early dietary control of children or mothers at risk, is on present evidence not well supported.

Spot-blot analysis of sorted chromosomes assigns a fructose intolerance disease locus to chromosome 9

The aldolase B gene was mapped to chromosome 9 using a rapid gene mapping system. This system uses a dual-laser sorter to identify and separate metaphase human chromosomes stained with either DIPI-chromomycin or Hoechst-chromomycin. Chromosome panels were constructed from a normal cell line by sorting 22 chromosome fractions directly onto nitrocellulose filters. Twelve labeled gene probes hybridized to the sorted chromosomal DNA fractions predicted by previous chromosome assignments. Eighteen newly cloned genes have been mapped using the same protocol.

Triosephosphate isomerase deficiency: 2 new cases

2 new cases of triosephosphate isomerase (TPI) deficiency associated with severe haemolytic anaemia in 2 unrelated Italian families are described. Only 1 case was extensively investigated. TPI deficiency was detectable in erythrocytes, leucocytes, platelets and plasma. The mutant enzyme showed normal Km for GAP and increased Km for DHAP, with an higher than normal equilibrium constant, decreased thermostability, and abnormal electrophoretic pattern due to the lack of the fastest moving component. The immunological characterization revealed a lower than normal inactivation by specific antiserum, while the double immunodiffusion pattern and the precipitin curve were normal. Lymphocyte, granulocyte and platelet functions were impaired.

DNA analysis in patients with hereditary fructose intolerance

Restriction fragments of the aldolase B gene were studied in 11 patients with hereditary fructose intolerance and compared with the normal pattern. No major deletion of the gene was observed. One patient was found to be a compound heterozygote since one allele with normal restriction sites was inherited from the mother and the other with an abnormal Bam HI site was inherited from the father. The anomaly of the Bam HI fragment observed in this family was not found in 62 normal controls from the same origin as the patient.

Detection of heterozygotes for fructose 1,6-diphosphatase deficiency by measuring fructose 1,6-diphosphatase activity in their cultured peripheral lymphocytes

The fructose 1,6-diphosphatase activities in peripheral lymphocytes from the parents of a patient with fructose 1,6-diphosphatase deficiency were lower than the mean value of normal controls, but the value of the mother overlapped lower values for normal controls. The fructose 1,6-diphosphatase activities in lymphocytes of normal adults and the parents increased progressively during in vitro culture, but no enzyme activity could be detected in the lymphocytes of the patient even after culture. None of the values for the parents overlapped those of normal controls on either day 5 or 10 of culture. Thus, it seems probable that heterozygotes for fructose 1,6-diphosphatase deficiency can be distinguished from normal individuals by measuring the fructose 1,6-diphosphatase activity in their cultured lymphocytes.

Canine fucosidosis: a biochemical and genetic investigation

Plasma and leucocytes from six springer spaniels with clinical signs of fucosidosis had low activities of alpha-L-fucosidase. Fucosidase activities in plasma and leucocytes from parents of springers with fucosidosis were approximately half those in non-springer dogs. Examination of pedigree information in relation to classifications based upon plasma and leucocyte assays provided convincing evidence that fucosidosis is inherited in an autosomal recessive manner and that it is possible to detect heterozygotes using plasma and leucocyte assays.

Allelic heterogeneity in adult hereditary fructose intolerance. Detection of structural mutations in the aldolase B molecule

Hereditary fructose intolerance (HFI) is a disorder of visceral carbohydrate metabolism which is transmitted as a recessive character of moderate to high gene prevalence. The condition is caused by enzymic deficiency of aldolase B and is associated with the synthesis of inactive enzyme protein. The molecular structure of aldolase B was examined in tissue samples from four adult patients who were the offspring of non-consanguineous unions. Titration of aldolase protein, by radioimmunoassay, showed that antibody recognition of the inactive enzyme was attenuated differently in two unrelated HFI patients. The existence of separate structural lesions was confirmed by protein blotting and immunodetection of enzyme subunits after sodium dodecyl sulphate/polyacrylamide electrophoresis. In one patient the subunit size was identical to wild type (Mr 38,000) and in the other, a single faint band (Mr 39,000) was identified. Radioimmunotitration studies, in two affected offspring of this latter patient by a proven HFI carrier, also revealed differences in antibody recognition. Segregation of different mutant alleles within this kindred demonstrates heterogeneity in HFI occurring at the same genetic locus. Variations in apparent immunoreactivity of aldolase B in HFI are thus related to overt modification of enzyme subunits and indicate that the disorder results principally from structural rather than regulatory mutations in the aldolase B gene.

Alterations in cultured fibroblasts of sibs with an infantile form of a free (unbound) sialic acid storage disorder

Cultured fibroblasts from two sibs with generalized hypertonia, hepatosplenomegaly, and psychomotor retardation within the first year of life were found to have unusual morphologic features. When examined by phase microscopy, the unstained and unfixed cells contained a large number of vacuolated structures whose gross appearance resembled that of a honeycomb in the cell cytoplasm. Electron microscopy studies, following fixation, showed the "honeycombing" to be the result of numerous, closely packed, cytoplasmic, membrane-bound vacuoles. In some of these structures the remains of fibrilogranular material could be detected. Biochemical analysis of crude sonicates of these cells revealed increased levels (4--7 x N) of an acid soluble component that reacted with thiobarbituric acid. Analysis of trimethylsilyl derivatives of this material by gas liquid chromatography and mass spectrometry showed it to be indistinguishable from sialic acid (N-acetylneuraminic acid). Quantitation of this material from the cells of one of the sibs after isolation on a Dowex column yielded 39.8 nmoles of free (unbound) sialic acid per mg protein whereas normal fibroblasts had 1--2 nmoles per mg. Bound sialic acid levels were at the upper limits of normal (24.8 versus 11--23 nmoles per mg protein). The concentration of cytidine monophosphate-sialic acid was normal. After incubation of the patient's fibroblasts with [3H]-N-acetylmannosamine for 72 h, there was a 7-fold increase (compared to normal fibroblasts) in the amount of radioactivity in free sialic acid present in the acid soluble fraction. The amount of labeled, bound sialic acid in the acid-insoluble pool, however, was the same in both patient and control fibroblasts.

Caprine beta-mannosidosis: clinical and pathological features

Beta-mannosidosis, an inherited defect of glycoprotein catabolism associated with deficiency of tissue beta-mannosidase and accumulation of Man(beta 1-4)GlcNAc and Man(beta 1-4)GlcNAc(beta 1-4)GlcNAc, appeared in four of 13 offspring of a single pair of clinically normal, related Nubian goats. Neurological examinations revealed that all four affected goats were unable to rise or walk. All had facial dysmorphism, dome-shaped skulls, small palpebral fissures, carpal contractures, hyperextension of the pastern joints, proximal muscle atrophy, intermittent ocular oscillations resembling pendular nystagmus, marked intention tremor, and deafness. With intensive care, three affected kids were hand-reared and then killed at 1, 7, and 21 days of age. Macroscopically, there were paucity of myelin in the cerebral and cerebellar hemispheres and ventricular dilatation. Microscopically, the extent and distribution of cytoplasmic vacuolation, myelin paucity, axonal spheroids, and filamentous expansions were evaluated in the cerebrum, cerebellum, brainstem, spinal cord, and peripheral nerves of the four affected kids and two age-matched, clinically normal kids. Widespread cytoplasmic vacuolation correlated with the previously reported accumulation of oligosaccharides in the brain and kidney and the deficiency of tissue beta-mannosidase. beta-Mannosidosis, not yet identified in man or other species, is characterized by distinctive neonatal clinical, pathological and biochemical features which differentiate it from the alpha-mannosidosis and other inherited diseases of glycoprotein catabolism.

[Hereditary fructose intolerance]

Two cases of hereditary fructose intolerance are reported. In the first one the symtomatology has started with an acute hepatic failure; the second one has come to our observation with a diagnosis of intrahepatic biliary duct atresia. It is underlined the difficulty of a differential diagnosis, in infants with serious hepatic failure, between infectious, metabolic and others illnesses.

Mannosidosis in two brothers: prolonged survival in the severe phenotype

Two cases of mannosidosis are reported in brothers, one aged 41 years at death, the other aged 40 years and still alive. These patients are the oldest reported in the literature. Prolonged survival has previously been associated with the milder Type II phenotype. In addition to the characteristic clinical and radiological features of mannosidosis, both had severe joint destruction, which may be related to abnormal lysosomal enzymes in cartilage. The activity of acidic alpha-mannosidase was markedly reduced in plasma, leucocytes and fibroblasts, and the altered kinetic and physical properties are described.

Molecular studies of liver aldolase B in hereditary fructose intolerance using blotting and immunological techniques

Hereditary fructose intolerance is due to a deficiency of liver aldolase (aldolase B). Little is known about its molecular mechanisms. We have tried to demonstrate the presence of the molecule and have explored the possibility of genetic heterogeneity. Liver samples from fifteen cases of hereditary fructose intolerance due to aldolase B deficiency were studied by various electrophoretic techniques. After electrophoresis on polyacrylamide gels, proteins were electrophoretically transferred on to nitrocellulose filters. They were treated with specific antialdolase B antibodies, and then with radioiodinated protein A, followed by autoradiography. Investigations included: (a) sodium dodecyl sulphate electrophoresis, in order to detect the presence of immunologically reactive molecules and to estimate the subunit size; (b) attempts to discover charge anomalies of the native molecule and of its subunits, by the use of: Isoelectric focusing of the native enzyme. Isoelectric focusing and non-equilibrium pH gradient electrophoresis (NEPHGE) after dissociation in urea. The major results were the following: (1) In all cases a cross-reacting material was found, with a molecular subunit size of 38000, indistinguishable from that of controls. (2) Evidence for molecular heterogeneity of the disease was provided by two types of data: amount of apparent immunologically reactive protein, which varied from less than 3% to 100% of that of controls; and charge data, aldolase B from seven patients showing an increased negative charge and from one patient a normal charge.

'Pseudohypertriglyceridemia' caused by hyperglycerolemia due to congenital enzyme deficiency

A 76-year-old man was found to have a false hypertriglyceridemia due to a 40-fold increased glycerolemia. This metabolic change was due to a deficiency in glycerol kinase (ATP:glycerol phosphotransferase, EC 2.7.1.30) activity in the cells of this patient as shown by incubation of his white blood cells with [14 C]glycerol. Several chromatographic analyses and quantitative assays were performed on plasma and urine of this patient and of his relatives. The small number of this family's members did not allow to specify the mode of transmission of this genetic trait.

[Hypercalciuria and hereditary fructose intolerance (author's transl)]

Hereditary fructose intolerance includes a dysfunction of the proximal renal tubule, which disappears when fructose is excluded from the diet. A 46 month-old girl, fed with such a fructose-free diet since the age of 4 months, presented with a renal hypercalciuria. The significance of this disorder is discussed.

Genetic and demographic characterization of a population with high incidence of fucosidosis

A random sample of unrelated students living in Grotteria and Mammola, two villages of Southern Italy from where most of the Italian patients affected with fucosidosis originate, was analyzed for seven red cell enzyme polymorphisms and seven blood group polymorphisms. The observed gene frequencies are not significantly different from those typical of Southern Italy. Demographic data on the same sample were also collected and indicate isolation and high inbreeding in these villages.

Apparently normal extracellular acidic alpha-mannosidase in fibroblast cultures from patients with mannosidosis

Fibroblasts from patients with mannosidosis, cultured in medium supplemented with fetal calf serum from which acidic alpha-mannosidase (alpha-D-mannoside mannohydrolase, E.C.3.2.1.24) has been removed, secreted a normal amount of apparently unaffected acidic alpha-mannosidase into fetal calf serum-free medium. Both the intracellular and extracellular acidic alpha-mannosidase activities were completely precipitated by antiserum to placenta alpha-mannosidase B. In contrast to the heat-lability of the intracellular acidic alpha-mannosidase and its low affinity for artificial mannoside substrate, the extracellular enzyme exhibited both normal thermostability and normal kinetics. Mixing experiments with the intercellular enzymes suggested that the decreased activity in the patients' fibroblasts is not the effect of an inhibitor or absence of an activator. However, incubation of the mannosidosis extracellular enzyme with either normal or patient cell lysate resulted in a partial loss of activity, whereas an additive value was observed with the normal extracellular enzyme. In contrast to normal culture medium, the medium from mannosidosis cell culture was unable to enhance the rate of reduction of intracellular radioactivity in mucolipidosis type II fibroblasts precultured in the presence of radiolabeled mannose. These findings suggest that the defect in mannosidosis is expressed only after the enzyme has been delivered to lysosomes and presumably undergone some form of processing there.

[Phenotypes in heteroglycanoses and sphingolipidoses (author's transl)]

Sphingolipidoses and heteroglycanoses are inborn errors of the carbohydrate metabolism. Biochemically and clinically hetero-glycanoses are sub-divided into mucopolysaccharidoses, oligosaccharidoses and mucolipidoses. These disorders of complex carbohydrate metabolism are due to the inborn defect of one or more lysosomal enzymes which in turn cause an intracellular accumulation of not-degraded complex carbohydrates corresponding to a wide pattern of clinical expression and symptomatology ranging from psychomotor retardation without any dysmorphic signs to severe features of a storage disease with dwarfism, peculiar facial appearance, organomegaly and skeletal changes. Investigations of recent years revealed that there is tremendous phenotypic variation even within diseases caused by a deficiency of the same enzyme. On the other hand, clinically indistinguishable phenotypes may be caused by the defect of different enzymes.

Mannosidosis: two brothers with different degrees of disease severity

Two siblings with different degrees of mental retardation, skeletal dysplasia, coarse facies, delayed speech, motor incoordination, recurrent respiratory infections, and immunological abnormalities, were found to have deficient alpha-mannosidase activity. Cultured skin fibroblasts in one sib were markedly deficient in alpha-mannosidase while all other lysosomal enzymes tested were within the normal range. The more severely affected sib came to autopsy and was found to have "washed-out" appearing cortical neurons and marked histiocytosis effacing lymph node architecture and partially replacing the bone marrow. The post-mortem brain and liver samples demonstrated a deficiency in alpha-mannosidase relative to the elevations of other lysosomal enzymes. Although the patterns of abnormalities in the two cases closely match those of descriptions of "type II" and "type I" mannosidosis respectively, the variation should be due to genetic modifiers or environmental effects since the brothers must have shared similar alpha-mannosidase mutations. Immunologic abnormalities present in the more severely affected sib suggest that the differential survival seen in mannosidosis types I and II may be due to differences in their immune systems.

Eleven cases of hereditary fructose intolerance in one Swiss family with a pair of monozygotic and of dizygotic twins

A large pedigree of one Swiss family with 11 cases of hereditary fructose intolerance (HFI) is presented, among them a pair of monozygotic twins with HFI and a pair of dizygotic twins one of whom had the disorder. The clinical course of undiagnosed babies with HFI at home is described. The case histories point out the importance of the mother's awareness of the situation since in none of the 11 cases the corrected diagnosis of HFI was made by a physician.

Familial Fanconi syndrome with malabsorption and galactose intolerance, normal kinase and transferase activity. A report on two siblings

Two siblings of Turkish-Assyrian extraction, whose parents were first cousins, had poor appetite, slow weight gain and retarded psychomotor development. When given milk the galactose concentration in blood increased. An oral galactose load showed a markedly reduced capacity to metabolize galactose. Fanconi syndrome was present as in classical galactosemia. A galactose-free diet reduced the aminoaciduria but did not normalize the renal tubular function nor the children's general condition. Galactokinase and galactose-1-phosphate uridyltransferase activities in red blood cells were normal. The physical appearance of the children (sparse subcutaneous fat, thin extremities and distended abdomen) and the results of vitamin A and xylose absorption tests, were in accordance with a malabsorption condition. Glucose, however, seemed to be absorbed normally from the gut. There was no evidence of primary liver disease. Since the condition did not normalize with a galactose-free diet, an enzyme defect of galactose metabolism is unlikely. Instead, a more general transport defect with autosomal recessive inheritance is proposed.

Fucosidosis: severe phenotype with survival to adult age

A male patient with fucosidosis exhibited the following characteristics: 1. Early onset and rapid progression of neurological symptoms. 2.Skin changes compatible with angiokeratoma corporis diffusum. 3. Complete or nearly complete deficiency of alpha-fucosidase. 4. Survival to adult age (20 years). The deficiency of alpha-fucosidase was demonstrated in liver, tears, urine, sediment, and cultured fibroblasts. We conclude that severe deficiency or complete absence of alpha-fucosidase does not by itself preclude survival to adult age.

Two patients with an unusual form of type II fucosidosis

Two brothers with an unusual form of fucosidosis are presented, providing further evidence for the clinical heterogeneity of the disease. The patients have several characteristics of type II, but from the point of view of progression rate and survival, they resemble more type III. However, the characteristic skin lesions of type III are not seen. In contrast to all other subtypes, a dry, thin skin is observed. The authors tend to classify these patients as a "slow motion" type II variant. Both in leukocyte lysates and plasma, severe alpha-L-fucosidase deficiency was established. In the parents, intermediate alpha-L-fucosidase activities were observed in leukocytes, but normal values in plasma, indicating that plasma is not suitable for carrier detection in this family. It is felt that no conclusions regarding clinical subtypes of fucosidosis can be drawn without careful characterization of the mutant enzyme in the primarily affected tissues.

Comparison of dietary habits and dental health of subjects with hereditary fructose intolerance and control subjects

Persons with HFI follow a lifelong, self-imposed, sucrose-restricted diet in which foods containing sucrose are consumed infrequently. Our subjects with HFI had a total sucrose intake that was approximately 5% that of control subjects and had a caries score (DMFS) that was less than 10% that of control subjects. No significant differences were found in the oral hygiene status (plaque or oral hygiene indexes) of the two groups. Foods containing starch, in the absence of sucrose, are not articularly inducive to caries. The daily intake of sucrose of the control group was less than expected. Consumption of sucrose is, therefore, less than estimates calculated by per capita sucrose disappearance. We consider that caries is initiated when the sucrose content of the diet and the frequency of ingestion exceed a low limit.

[Biochemical diagnosis of mannosidosis in 2 families]

On examination of children with primary diagnosis of mucopolysaccharidosis distinct deficiency of acid alpha-D-mannosidase was found in leukocytes of the children and decrease in the enzymatic activity down to the level of heterozygote carriers was observed in their parents. The activity of neutral alpha-D-mannosidase was within the range of normal values in the children and parents. The examination carried out enabled to establish the diagnosis the hereditary lysosomal disease of accumulation--mannosidosis--in the children.