[Congenital hemolytic anemia due to glucose-6-phosphate dehydrogenase deficiency]

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common enzyme defect with a wide range of clinical manifestations that can be severe. A variety of factors including many medications can induce hemolytic episodes. Screening for G6PD deficiency is required before use of some drugs especially primaquine or dapsone.

The contribution of Ca+ calmodulin activation of human erythrocyte AMP deaminase (isoform E) to the erythrocyte metabolic dysregulation of familial phosphofructokinase deficiency

Erythrocyte membrane leakage of Ca2+ in familial phosphofructokinase deficiency results in a compensatory increase of Ca2+-ATPase activity that depletes ATP and leads to diminished erythrocyte deformability and a higher rate of hemolysis. Lowered ATP levels in circulating erythrocytes are accompanied by increased IMP, indicating that activated AMP deaminase plays a role in this metabolic dysregulation. Exposure to a calmodulin antagonist significantly slows IMP accumulation during experimental energy imbalance in patients' cells to levels that are similar to those in untreated controls, implying that Ca2+-calmodulin is involved in erythrocyte AMP deaminase activation in familial phosphofructokinase deficiency. Therapies directed against activated isoform E may be beneficial in this compensated anemia.

Prenatal diagnosis and management of fetal xerocytosis associated with ascites

OBJECTIVES

To discuss the prenatal diagnosis and management of fetal xerocytosis associated with ascites.

CASE REPORT

A 29-year-old woman with hereditary xerocytosis was found to present a fetus with severe ascites on the 20-week scan. Cordocentesis showed mild anemia and blood transfusion was discarded. Ascites worsened and 2 weeks later a new cordocentesis showed lower hematocrit values. Blood transfusion was performed but ascites remained unchanged. Cordocentesis was repeated at 28 weeks and albumin was transfused. Fetal hemoglobin was within the normal range. Peak systolic velocity of the middle cerebral artery remained normal and correctly predicted mild anemia. Expectant management was followed. An elective cesarean section was performed at 32 weeks because of breech presentation and preterm labor which did not respond to aggressive tocolysis. A female newborn weighing 2,615 g was delivered and required paracenteses and exchange transfusion. The newborn was discharged at 4 weeks of life and at 2 months of age, the ascites resolved completely.

CONCLUSIONS

The mechanism of development of ascites in fetal xerocytosis remains unanswered. As ascites does not seem to be related to fetal anemia or hypoalbuminemia, does not substantially change after blood transfusion and tends to resolve in late gestation, a conservative management is reasonable if fetal anemia is not severe.

Pyruvate kinase deficiency in a Somali cat in Australia

A 7-year-old neutered male Somali cat, bred in Western Australia, was presented for investigation of jaundice and severe anaemia. Splenomegaly and hepatomegaly were evident on physical examination. Severe anaemia, along with leukopenia and increased liver enzymes, were present on laboratory evaluation. Clinical investigation identified cholangitis and treatment for this resolved the jaundice but failed to resolve the anaemia. Treatment for Mycoplamsa haemofelis was administered concurrently. Genetic testing was then performed and pyruvate kinase deficiency was identified, the first time this has been reported in an Australian cat. Treatment with immunosuppressive medication was not successful.

Coexistence of congenital red cell pyruvate kinase and band 3 deficiency

The authors report the case of a 9-year-old Caucasian girl, born in northern Portugal, with chronic nonspherocytic haemolytic anaemia and without family history of anaemia. The aethiological study of this anaemia revealed pyruvate kinase deficiency (PKD), because of two previously described mutations (426Arg-->Trp and 510Arg-->Gln). Since the blood smear revealed features not fully compatible with PKD diagnosis, additional tests were performed for the propositus and her parents, namely red blood cell membrane protein analysis. A decrease in proteins band 3 (15%) and 4.2 (18%) was found in the propositus. Her father presented only a decrease in band 3 (11%). Coexistence of PKD and erythrocyte membrane proteins deficiency in the same patient is very uncommon. Our findings suggest that a careful blood smear observation may lead to the identification of a combined deficiency in erythrocyte membrane proteins and enzymopathies.

Altered erythrocyte endothelial adherence and membrane phospholipid asymmetry in hereditary hydrocytosis

The risk for thrombosis is increased in patients with hereditary hydrocytosis, an uncommon variant of hereditary stomatocytosis. Erythrocytes from 2 patients with hydrocytosis were studied to gain insight into the mechanism of thrombosis in this disorder. Erythrocytes demonstrated abnormal osmotic scan ektacytometry and decreased erythrocyte filtration rates. There was also a mild increase in adherence of erythrocytes to endothelial monolayers in a micropipette assay. Adhesion of erythrocytes to the subendothelial matrix proteins thrombospondin and laminin, however, was not significantly increased. Percentages of hydrocytosis erythrocytes and reticulocytes with phosphatidylserine exposed on the outer surfaces were increased in both patients compared with healthy controls, indicating altered membrane phospholipid asymmetry. Increased phosphatidylserine exposure accelerating thrombin-forming processes has been proposed as a mechanism for thrombosis in sickle cell disease and beta-thalassemia and may play a similar role in hereditary hydrocytosis.

Molecular basis of red cell membrane disorders

We will consider an array of genetic disorders of the red cell membrane. Some affect well-known genes. The mutations of most cases of hereditary spherocytosis (HS) are located in the following genes: ANK1, SPTB, SLC4A1, EPB42 and SPTA1, which encode ankyrin, spectrin beta-chain, the anion exchanger 1 (band 3), protein 4.2 and spectrin alpha-chain, respectively. A dominant form of distal renal tubular acidosis also stems from distinct mutations in the SLC4A1 gene. The mutations responsible for hereditary elliptocytosis (HE) and its aggravated form, poikilocytosis (HP), lie in the SPTA1 and SPTB gene, already mentioned, and in the EPB41 gene encoding protein 4.1. Whereas in HS, the SPTA1 and SPTB gene mutations tend to abolish the synthesis of the corresponding chains, in HE/HP, they hinder spectrin tetramerization. Allele alpha(LELY) is a common polymorphic allele which plays the role of an aggravating factor when it occurs in trans of an elliptocytogenic allele of the SPTA1 gene. Southeast Asian ovalocytosis results from a 27- nucleotide deletion in the SLC4A1 gene. Besides these conditions in which the mutations were reached from known alterations in the proteins, other conditions required a positional cloning approach. Such are the genetic disorders of membrane permeability to monovalent cations. Knowledge is the most advanced as regards dehydrated hereditary stomatocytois (DHS). DHS was shown to belong to a pleiotropic syndrome: DHS + fetal edema + pseudohyperkalemia, which maps to 16q23-24. Concerning DHS and another disease of the same class, overhydrated hereditary stomatocytosis, splenectomy almost certainly appears to elicit thromboembolic accidents.

Chronic haemolytic anaemia and glucose-6 phosphate dehydrogenase deficiency. Case report and review of the literature

Deficiency in glucose-6-phosphate dehydrogenase (G6PD) is the most common enzymopathy, and more than 125 different mutations causing G6PD deficiency have been identified. Chronic haemolytic anaemia (CHA) associated with G6PD deficiency is rare, but there is a cluster of mutations causing CHA between amino acids 361-428 which are encoded by exon 10 of the G6PD gene. This region is involved in the dimer formation of the active G6PD enzyme and therefore plays an important role for enzyme stability and activity. Here, we report a 17-year-old patient with CHA, who carries a rare G --> A mutation at nucleotide 1160 which causes an R387H amino acid substitution. We review the reports of the seven previously described patients with this mutation, concluding that G6PD deficiency should be considered as a rare differential diagnosis of chronic haemolytic, non-spherocytic anaemia.

Band 3 anion exchanger and its involvement in erythrocyte and kidney disorders

Recent developments in the structure of erythrocyte band 3 and its role in hereditary spherocytosis and distal renal tubular acidosis are described. The crystal structure of the N-terminal cytoplasmic domain provides a basis for understanding the organization of ankyrin and other peripheral membrane proteins around band 3. Band 3 also binds integral membrane proteins, including the Rh protein complex and CD47. Band 4.2 is important in these associations, which link the Rh complex to the skeleton. It is suggested that band 3 forms the scaffold for a protein assembly that could transduce signals from the cell exterior and modulate the transport and mechanical properties of the erythrocyte. The involvement of band 3 in distal renal tubular acidosis is reviewed. The article discusses a likely mechanism for dominant distal renal tubular acidosis in which associations between the normal and mutant protein alter the plasma membrane targeting of the normal protein in the kidney.

Important region in the beta-spectrin C-terminus for spectrin tetramer formation

Many hereditary hemolytic anemias are due to spectrin mutations at the C-terminal region of beta-spectrin (the betaC region) that destabilize spectrin tetramer formation. However, little is known about the betaC region of spectrin. We have prepared four recombinant beta-peptides of different lengths from human erythrocyte spectrin, all starting at position 1898 of the C-terminal region, but terminating at position 2070, 2071, 2072 or 2073. Native polyacrylamide gel electrophoresis showed that the two peptides terminating at positions 2070 and 2071 did not associate with an N-terminal region alpha-peptide (Spalpha1-156) in the micromolar range. However, the peptides that terminated at positions 2072 and 2073 associated with the alpha-peptide. Circular dichroism results showed that the unassociated helices in both alpha- and beta-peptides became associated, presumably to form a helical bundle, for those beta-peptides that formed an alphabeta complex, but not for those beta-peptides that did not form an alphabeta complex. In addition, upon association, an increase in the alpha-helical content was observed. These results showed that the beta-peptides ending prior to residue 2072 (Thr) would not associate with alpha-peptide, and that no helical bundling of the partial domains was observed. Thus, we suggest that the C-terminal segment of beta-spectrin, starting from residue 2073 (Thr), is not critical to spectrin tetramer formation. However, the C-terminal region ending with residue 2072 is important for its association with alpha-spectrin in forming tetramers.

Successful treatment of neonatal rhesus hemolytic anemia with high doses of recombinant human erythropoietin

The authors report the use of high-dose recombinant erythropoietin (r-HuEPO) in a full-term newborn baby with severe postnatal rhesus hemolytic anemia (RHA). Hemoglobin (Hb) value and reticulocyte count at day 13 of life were 59 g/L and 234 x 10(9)/L, respectively. Three days after the r-HuEPO (870 U/kg/d) administration, reticulocyte count had increased more than 4-fold and Hb rose to 73 g/L. r-HuEPO was gradually decreased after 18 days of treatment. No major side effect was observed. In selected cases of severe anemia due to hemolytic disorders, transfusions may be avoided by the use of high doses of r-HuEPO.

Haemolytic anaemia and exercise intolerance due to phosphofructokinase deficiency in related springer spaniels

Phosphofructokinase (PFK) deficiency is an autosomal recessive inherited disorder in dogs causing haemolytic crises and exertional myopathy. The clinical signs may be confused with those of recurrent immune-mediated haemolytic anaemia. The deficiency has been commonly observed in field trial (working) English springer spaniels (ESSPs), but also in the conformation line of ESSPs in the USA over the past two decades. This report documents the first family of ESSPs found with PFK deficiency in Europe. Two related adult ESSPs in Denmark had intermittent signs of pigmenturia after exercise (hunting) and had evidence of a regenerative haemolytic anaemia. Based upon DNA sequencing data, both dogs had the previously described nonsense point mutation in the muscle-type PFK gene (delta2228G-->A). Study of 17 related family members using a simple and accurate PFK-DNA test revealed one additional PFK-deficient dog (with minor exercise intolerance), nine carriers and seven normal (or 'clear') ESSPs. Recently, the authors have also identified PFK carriers and affected ESSPs in the UK. Screening for PFK deficiency is recommended for ESSPs with suspicious clinical signs and before using any for field trials or breeding in order to prevent the further spread of this hereditary disorder.

To transfuse or not to transfuse: iatrogenic compromise of women's reproductive careers

A 21-year-old Indo-Asian woman, who had arrived in the UK 5 months before presentation, consulted her general practitioner because of tiredness and shortness of breath on climbing stairs. There were no significant factors in her history, except that she did not eat red meat. Initial investigation revealed a severe anaemia with a haemoglobin (Hb) concentration of 4.6 g/dl, mean cell volume (MCV) of 49.4 fl, mean cell haemoglobin (MCH) of 11.5 pg, white cell count of 7.4 × 109/litre and a platelet count of 583 × 109/litre. She was promptly referred as an emergency to a general medical ward in a teaching hospital for further management. On admission, physical examination revealed pallor and a tachycardia of 110 beats/minute, but there ware no other significant findings. Her electrocardiogram was normal and there was no evidence of cardiac failure on chest X-ray. She was transfused three units of packed red cells. Subsequently she underwent further investigations, including Hb electrophoresis, vitamin B12 and folate levels, ferritin and transferrin levels, serum urea and electrolytes, liver function tests, blood film for malarial parasites, endomysial and gliadine antibodies, and comprehensive gastrointestinal tract work-up. All investigations were negative with the exception of a positive anti-gliadine immunoglobulin G. The diagnosis of iron deficiency anaemia of unknown cause was made. The patient was given dietary advice and was discharged back under her GP's care 6 months later, having maintained a normal Hb.

Haemoglobin Q-Thailand and hereditary spherocytosis in a Chinese family

A Chinese family with concurrent hereditary spherocytosis (HS) and haemoglobin (Hb) Q-Thailand is described. The Hb Q-Thailand mutation was found on the remaining alpha1 globin gene on a chromosome 16 containing the (-alpha 4.2) deletion. Active haemolysis in members of this family is segregated with the HS phenotype, and the Hb Q-Thailand in the heterozygous state does not seem to show any modulating effect on HS.

Haemolytic disease of the newborn due to anti-Ce

A baby was readmitted to the hospital 3 days after delivery when she developed jaundice. At admission, the direct antiglobulin test was also found to be positive. The baby required emergency exchange transfusion. A strongly reacting IgG anti-Ce (Rh7) was found in the serum of the mother. Severe haemolytic disease of the newborn due to anti-Ce is very rare. The mother's serum had been screened and found negative for red cell antibodies at 16 weeks gestation but the test was not repeated later in pregnancy when this antibody might have been detected.

[Glucose-6-phosphate dehydrogenase deficiency and hereditary hemolytic anemia]

G6PD deficiency is the most common enzymopathy in the world. The highest frequency values are found in tropical Africa, in the Middle East, in some areas of the Mediterranean, in tropical and sub-tropical Asia and in Oceania. This genetic defect shows sex linked inheritance and a marked heterogeneity. At least 400 abnormal variants with different biochemical characteristics and about 100 diverse mutations have been identified. In most cases the phenotypic expression is a marked decrease in erythrocyte G6PD activity. The most common clinical consequences are neonatal jaundice and sporadic haemolytic crises caused by a number of drugs, by infections or by ingestion of fava beans. A few cases of chronic non-spherocytic haemolytic anaemia associated with rare molecular variants have been reported. Early diagnosis, education and epidemiologic surveillance have been proved to be cornerstones in the prevention of the haemolytic disease. Therefore they should be taken into account in the national health programmes, especially in the countries with high prevalence rates.

[Diagnosis of pyruvate kinase deficiency in the presence of an elevated reticulocyte count]

HISTORY AND CLINICAL FINDINGS

Three members of one family (mother, now aged 44 years; daughter, now aged 23 years, and son, now aged 19 years) have had chronic haemolytic anaemia since their infancy. All three have had several blood transfusions a year because of haemoglobin (Hb) concentrations as low as 5 g/dl due to intermittent increases in haemolysis. Despite an unclear diagnosis all three had splenectomies: their spleens had been enlarged to about 5-7 cm below the rib margin. After splenectomy their haemoglobin concentration rose to 9-12 g/dl and the previously raised reticulocyte count of 150-250/1000 rose further to 400-700/1000. None of the patients had symptoms other than a slight decrease in exercise tolerance. They were admitted to hospital for further evaluation. Physical examination was unremarkable except for slight jaundice and well healed splenectomy scar.

TESTS

All three patients had normochromic haemolytic anaemia (Hb 10-12 g/dl), bilirubin 2-3 mg/dl, lactate dehydrogenase activity 400-600 U/l). The reticulocyte count was raised to 420-690/1000. In all of them pyruvate kinase (PK) activity was normal or slightly increased if related to Hb concentration. Reticulocytes from healthy persons were isolated by density-gradient centrifugation so that samples could be prepared with different numbers of reticulocytes: PK activity was found to be dependent on the sample's reticulocyte count. In the three patients PK deficiency could, therefore, only be diagnosed by taking into account the raised reticulocyte count.

CONCLUSION

As reticulocytes have a higher PK activity than erythrocytes the reticulocyte count must be taken into account when assessing the significance of a given value of this enzyme's activity.

Hemolytic anemia in the newborn

Evaluation of hemolytic anemia in the newborn may be complicated owing to the physiologic changes that occur during this time; however, the newborn period is a time when congenital red cell abnormalities may first present and when maternal factors need to be considered. In this article, an approach to the diagnosis of hemolytic disease in the newborn is reviewed. The unique properties of the neonatal red cell, the normal red cell changes present in the neonate, the potential congenital defects and maternal factors that may influence the associated clinical and laboratory findings consistent with the diagnosis of hemolytic anemia, and a brief review of the red cell disorders associated with hemolytic anemia in the newborn are discussed.

Congenital haemolytic anaemia associated with adenylate kinase deficiency

Chronic haemolytic anaemia associated with adenylate kinase (AK) deficiency is very rare and only seven cases in five families have been described. We present six children of one family who are deficient of this enzyme and in three of them a combined G6PD deficiency was found. AK deficiency was transmitted by an autosomal recessive gene and heterozygous state was not accompanied by disease, whereas homozygously affected individuals present a congenital chronic non-spherocytic haemolytic anaemia with haemoglobin levels of 8-9 g/dl. Patients also deficient in G6PD suffer from a more severe haemolytic anaemia with haemoglobin levels around 6 g/dl. The AK-deficient children are also mentally retarded. Splenectomy performed in five of the six patients resulted in complete remission of the haemolytic process.

Glucose 6-phosphate dehydrogenase deficiency and red cell membrane defects: additive or synergistic interaction in producing chronic haemolytic anaemia

We have investigated two unrelated patients with congenital haemolytic anaemia in both of whom we found a combination of hereditary spherocytosis (HS) and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Segregation of the two defects was documented in both families, who had different molecular abnormalities for both HS and G6PD deficiency. In one family the propositus had a reduced level of spectrin and G6PD Seattle (282Asp-->His). In the other family the propositus had a band 3 abnormality and was heterozygous for G6PD Mediterranean (188Ser-->Phe). From a comparison of clinical and haematological findings in family members with either or both abnormalities we conclude that in one case the two defects exhibited a synergistic effect, resulting in a severe chronic haemolytic anaemia; whereas in the other the association was simply additive.

[Hemolytic anemias due to enzymopathies]

The most inherited enzymopathies associated with hemolytic anaemias are due to enzyme deficiencies (as a consequence of either synthesis reduction or impairement of the enzyme function). Such deficiencies can disturb some metabolism of the red cells. The most of enzyme deficiencies are involved in glycolysis that represents the main source of energy for this cell. Generally the genetic transmission of these enzymopathies is recessive autosomal with the exception of two cases (glucose 6-phosphate dehydrogenase and phosphoglycerate kinase) which are X-chromosome-linked. It stands to reason that the only treatment of these enzymopathies is dependent on gene therapy, a fine future method. Nevertheless prenatal diagnosis can be considered in some cases that display particularly severe symptoms.

Pyruvate kinase deficiency. Association with G6PD deficiency

Images

Congenital haemolytic anaemia in a low birth weight infant due to congenital stomatocytosis

A baby girl born at 31 weeks gestation showed severe haemolytic anaemia and hyperbilirubinaemia which led to exchange transfusion within the first 12 hours of life. There was no blood group incompatibility between mother and child but there was a marked stomatocytosis of the baby's red blood cells. Family history revealed a congenital stomatocytosis in the mother. Biochemical characterization of the defect was performed. Phospholipid analysis of the erythrocyte membrane of mother and child showed an increase in phosphatidylserine with a compensatory decrease in phosphatidylcholine and phosphatidylethanolamine. SDS-electrophoresis showed multiple modifications of the protein pattern with a decrease in band 6, an increased content of band 4.1b, a slight decrease in band 7 and a clear change in the shape of the protein band 3 pattern. The results suggest that the basis of the observed abnormalities is a common defect in protein posttranslational modification, rather than multiple genetic defects in the synthesis of several proteins. Haematologic, biochemical and clinical course of the disease in this preterm infant are discussed.

[Neonatal blood group incompatibility due to anti-M antibodies]

Neonatal blood group antagonism due to anti-M antibodies is extremely rare. The case is reported of a neonate with moderately severe haemolytic anaemia due to anti-M which required two blood transfusions. Although anti-M antibodies are as a rule regarded as clinically irrelevant, and although they react almost exclusively at lower temperatures, they may in exceptional cases be demonstrated at 37 degrees C, as in the patient described; they may then cause haemolysis. Most strikingly, the direct Coombs test in this patient was negative; this phenomenon has been described before. In unexplained haemolytic anaemia of a newborn, even in the presence of a negative direct Coombs test, the possibility of blood group antagonism should be considered.

Haemolytic anaemia in analpha-lipoproteinaemia (Tangier disease): morphological, biochemical, and biophysical properties of the red blood cell

A patient with familial analpha-lipoproteinaemia (Tangier disease) was found to have stomatocytosis and haemolytic anaemia. The analysis of the red cell membrane constituents revealed a low cholesterol content (90 nmol/ml red cells, control 130 nmol/ml red cells), a decreased cholesterol/phospholipid ratio (0.54, control 0.78), high phosphatidylcholine (41.5%, control 30.6%) and low sphingomyelin (18.8%, control 27.6%). The electrophoretic membrane protein pattern was normal. Osmotic gradient ektacytometry and osmotic resistance showed a decreased surface/volume ratio, which caused an increased filtration resistance in 3 microns pores. The elasticity of the membrane was unchanged. Functional membrane properties were altered: the anion exchange rate was increased, whereas alkali cation fluxes were normal. The capacity to release vesicles was reduced. This case represented a new type of stomatocytosis. It contributes to the understanding of the role of cholesterol and phospholipids in the red cell membrane and biomembranes in general.

Erythrocyte pyruvate kinase deficiency. A case of severe congenital hemolytic anemia

Although it occurs rarely, erythrocyte pyruvate kinase deficiency is a cause of neonatal jaundice and anemia across many ethnic and geographic groups. In this report of a Missouri case, an infant with this condition was also found to have Pelger-Huet leukocyte anomaly.

Aplastic crisis due to human B19 parvovirus infection in red cell pyrimidine-5'-nucleotidase deficiency

Two siblings with chronic hemolytic anemia due to red cell pyrimidine-5'-nucleotidase (P-5'-N) deficiency, presented within a few days of each other with a febrile illness and pancytopenia. The cause of the aplastic crisis was an acute infection with human B19 parvovirus (B19 HPV) as proven by immunoelectron microscopy and DNA hybridization. This is the first report on the association of B19-HPV-related aplastic crisis with P-5'-N deficiency.

A new glucose-6-phosphate dehydrogenase variant (G6PD Tsukui) associated with congenital hemolytic anemia

A new glucose-6-phosphate dehydrogenase (G6PD) variant associated with chronic nonspherocytic hemolytic anemia was found in a 20-year-old Japanese male who showed mild hemolysis after an upper respiratory tract infection. The patient had been noted to have jaundice and reticulocytosis several times before this episode. The enzyme activity of the variant was 1.5% of normal. The enzymatic characteristics were slow anodal electrophoretic mobility, high Km G6P, normal Km NADP, decreased heat stability, and a normal pH optimum. From these results, the enzyme was considered to be a new class 1 variant and was designated G6PD Tsukui.

[The importance of human parvovirus infections in pediatrics]

Human Parvovirus (HPV) is a DNA virus which causes the aplastic rises in the chronic hemolytic anemias. HPV IgG was found positive in the newborns with CMV and Rubella negative congenital intrauterine infection. Recently, it was reported that nonimmunologic hydrops fetalis caused by HPV Now, HPV (especially B 19) is a well known virus which takes significant place in the public health and pediatrics.

Hemoglobin Hammersmith as the cause of severe hemolytic anemia in a Chinese girl

Hemoglobin Hammersmith, a rare unstable hemoglobin, was diagnosed in a 4-year-old Chinese girl living in Los Angeles. She presented with the typical manifestations of this disorder, including neonatal hyperbilirubinemia, followed by increasing hepatosplenomegaly, jaundice, bilirubinuria, and a severe hemolytic anemia exacerbated by mild infections. The most prominent manifestations of the peripheral smear were polychromasia, normoblastemia, and basophilic stippling. The diagnosis was confirmed by several techniques.