[Syndrome of alimentary hemolysis and its distribution in Spain].
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We attempted to characterize biochemically glucose-6-phosphate dehydrogenase (G6PD) variants in Iraqi individuals. Thus 758 healthy Iraqi males aged 18-60 years were randomly selected and 46 (6.1%) were G6PD deficient. Although the predominant non-deficient G6PD phenotype was G6PD B (92.6%), G6PD A+ was found in polymorphic frequency (1.3%). In the deficient group, 31 cases were fully characterized, including 17 cases with features consistent with G6PD Mediterranean variant, while 12 had other biochemical features and were labelled as non-Mediterranean variant. The remaining two deficient cases were characterized as G6PD A- variant. The presence of a significant number of non-Mediterranean variant was unexpected and may be related to the more heterogeneous background of the Iraqi people.
In the present study, plasma lipid concentrations were determined at different times after admission in sera from G6PD-deficient children during haemolytic crisis induced by fava bean ingestion. Reductions in total, LDL and HDL cholesterol were found in association with the maximum of bone marrow hyperplasia. A return towards normal values occurred with regression of the disease. No changes in other lipid parameters were observed. These data suggest that alterations of lipoprotein pattern, other than in experimental animals, are also present in humans with non-malignant proliferative processes. These changes appear to be a consequence of the disease, probably due to an increased utilization of cholesterol by proliferating cells.
We report seven consecutive episodes of acute massive haemolysis accompanied by symptomatic anaemia and gross haemoglobinuria in six boys with glucose-6-phosphate dehydrogenase deficiency seen in a regional hospital during a 12-year period. They presented at a mean age of 5.5 years (range, 1.5-11.3 years) with trough haemoglobin levels between 35 and 84 g/L. Two children developed transient renal impairment. Five children required erythrocyte transfusion, of whom one underwent exchange transfusion during the oliguric phase. Three patients required intensive care but all recovered from the haemolysis. The probable precipitating factors included consumption of fava beans (n=2), exposure to mothballs (n=1), treatment with herbal medicine or intramuscular injection of unknown nature (n=3), and upper respiratory tract infection (n=1). Although uncommon, acute massive haemolysis remains a life-threatening complication in children with glucose-6-phosphate dehydrogenase deficiency. Improvement in patient education and public health measures is suggested.
Two male subjects are described, with unusual clinical presentations and with hitherto undescribed G6PD variants. The first, of Italian extraction, suffered from severe neonatal jaundice following maternal ingestion of fresh broad beans (Vicia fava) both prenatally and postnatally: the expression of the enzymatic defect was much more severe in the neonatal period than on retesting in adolescence, when biochemical characterization showed unique features which justify designation as a new variant Gd(+) Alexandra. The second patient, a boy of Maltese extraction who was found to have bilateral lamellar cataracts at the age of 4 years, was identified as G6PD deficient only as a result of a survey of children of Mediterranean origin with unexplained cataract formation; he has approximately 15% of normal enzyme activity, with another unique combination of biochemical characteristics which has led to its designation as Gd(-) Camperdown. Although this association may be coincidental, it prompts further attention to the possibility that under certain circumstances G6PD deficiency may favor cataract formation. The two cases illustrate the value of characterization of the mutant enzyme whenever unexpected clinical or laboratory results are obtained.
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Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the commonest enzyme disorder of human beings and a globally important cause of neonatal jaundice, which can lead to kernicterus and death or spastic cerebral palsy. It can also lead to life-threatening haemolytic crises in childhood and at later ages, by interacting with specific drugs and with fava beans in the diet. The complications of G6PD deficiency can largely be prevented by education and information, and neonatal jaundice can be successfully treated by phototherapy, a cheap and simple approach suitable for use in primary health care. This update describes developments in the methodology for characterizing G6PD deficiency, recent knowledge of the factors that can cause haemolysis, community approaches for prevention of haemolytic crises and neonatal jaundice, and the implications of recent advances at the DNA level.
In favic crises the effective surface area of red cells is reduced by a mechanism called membrane cross bonding (Fischer et al., Brit. J. Haematol. 59, 159, 1985). In these crises massive intravascular hemolysis is observed the cause of which is unknown. One possibility is mechanical hemolysis of cross-bonded red cells that cannot negotiate the microcirculation due to their decreased effective surface area. To investigate this possibility critical phenomena of red cell behavior in the microcirculation were studied using Laplace's law. In model calculations an idealized vessel geometry was used: a funnel in which the angle of the conical part and the radius of the cylindrical part were varied. A map of these two parameters was established showing where red cells either enter the funnel or get stuck and where they would hemolyse under a pressure difference of 3 mm Hg. Adopting a teleological point of view it was assumed that red cell and vessel geometry are mutually adapted. Based on this assumption those combinations of the two parameters cone angle and radius were found that allow the passage of the complete population of normal red cells without hemolysis. Assuming a reduction in red cell surface area similar to that observed in favic crises it was found that only a small portion of the population would hemolyse. Therefore, mechanical hemolysis may not suffice to explain the observed intravascular hemolysis.
RBCs from four glucose-6-phosphate dehydrogenase (G6PD)-deficient (Mediterranean variant) subjects were studied during fava bean hemolysis. In the density-fractionated RBC calcium level, Ca2+-ATPase activity, reduced glutathione level, and ghost protein pattern were studied. In the bottom fraction, containing most heavily damaged RBCs, calcium level ranged from 143 to 244 mumol/L RBCs (healthy G6PD-deficient controls: 17 +/- 5 mumol/L RBCs). The Ca2+-ATPase activity ranged from 0.87 to 1.84 mumol ATP consumed/g Hb/min (healthy G6PD-deficient controls: 2.27 +/- 0.4). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of ghosts showed: (1) the presence of high mol wt aggregates (in three cases they were reduced by dithioerythritol; in one case, only partial reduction was possible); (2) the presence of multiple, scattered new bands; and (3) the reduction of band 3. Oxidant-mediated damage to active calcium extrusion, hypothetically associated with increased calcium permeability, may explain the large increase in calcium levels. They, in turn, could activate calcium-dependent protease activity, giving rise to the profound changes in the ghost protein pattern.
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Deficiency in human G-6PD is a widespread X-linked disorder, which is mainly characterized by susceptibility to hemolytic anaemia after the ingestion of certain drugs or toxic substances (e.g. pyrimidine derivates contained in fava beans). G-6PD deficiency in hemizygous males in easily detectable since enzymatic activity is almost absent. In heterozygous subjects the determination of enzymatic activity on red cell lysate cannot detect a partial G-6PD deficiency. Cytochemical methods as methemoglobin reduction test or tetrazolium reduction test are more sensitive than spectrophotometric quantitative test, but are not suitable for screening purposes. We measured both G-6PD activity and 6-PGD activity in G-6PD heterozygous females and we evaluated the G-6PD/6PGD ratio. We tested this ratio also in thalassemic traits and in G-6PD heterozygotes with thalassemic trait in order to detect the interference of thalassemic pathology with the phenotypic expression of the gene for G-6PD. We found that the mean G-6PD values were statistically reduced in G-6PD heterozygous females; on the contrary the measurement of true G-6PD activity alone is not a good tool for discriminating heterozygous subjects with and without thalassemic trait. Actually 100% and 79% of values observed were in the normal range +/- 2 DS respectively. The mean G-6PD/6-PGD ratio in heterozygotes for G-6PD deficiency with and without thalassemic trait was lower than normal and the individual values of G-6PD/6-PGD ratio were in the normal range +/- 2 DS only in a few subjects (8.3% and 10.7% respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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A high incidence of hereditary blood anomalies (particularly Pelger-Huët's congenital granulocytic anomaly and Lepore haemoglobinopathy) is reported in the people of the Sangro Valley (Abruzzo, South Italy). The clinical, haematological, genetic and demographic implications of the high incidence of these pathologies are discussed.
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