Optic neuritis in CD59 deficiency: an extremely rare presentation

BACKGROUND

CD59 is the principal cell inhibitor of complement membrane attack on cells. Stroke, peripheral neuropathy, and recurrent central nervous system attacks have been reported in patients with inherited CD59 deficiency. In this paper, we report a patient with CD59 deficiency associated with two attacks of demyelinating peripheral neuropathy and the third attack as an isolated optic neuritis.

CASE

An 8-month-old girl whose sibling died at 12th month of age with recurrent weakness episodes responsive to intravenous immune globulin treatment, presented with weakness in legs and poor sucking. Weakness episodes with neurogenic electromyography suggested CD59 deficiency. Immunophenotypic analysis with flow cytometry showed CD59 deficiency. Sanger sequencing of CD59 gene revealed a homozygous c146delA (p.Asp49Valfs*32) mutation. First two attacks were treated with intravenous immunoglobulin therapy without any sequalae. Third attack was an isolated optic neuritis which could not be explained by any other entity. The patient had no response to intravenous immunoglobulin but benefited from pulse steroid therapy. Eculizumab was started every two weeks in order to prevent possible advanced attacks and to reduce their severity.

CONCLUSION

Although it is a rarely reported disease, better recognition of CD59 deficiency by pediatric neurologists is necessary because it is curable. In addition to different presentations reported, optic neuritis may also be a manifestation of CD59 deficiency.

Evolutionary dynamics of paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal blood disorder characterized by hemolysis and a high risk of thrombosis, that is due to a deficiency in several cell surface proteins that prevent complement activation. Its origin has been traced to a somatic mutation in the PIG-A gene within hematopoietic stem cells (HSC). However, to date the question of how this mutant clone expands in size to contribute significantly to hematopoiesis remains under debate. One hypothesis posits the existence of a selective advantage of PIG-A mutated cells due to an immune mediated attack on normal HSC, but the evidence supporting this hypothesis is inconclusive. An alternative (and simpler) explanation attributes clonal expansion to neutral drift, in which case selection neither favours nor inhibits expansion of PIG-A mutated HSC. Here we examine the implications of the neutral drift model by numerically evolving a Markov chain for the probabilities of all possible outcomes, and investigate the possible occurrence and evolution, within this framework, of multiple independently arising clones within the HSC pool. Predictions of the model agree well with the known incidence of the disease and average age at diagnosis. Notwithstanding the slight difference in clonal expansion rates between our results and those reported in the literature, our model results lead to a relative stability of clone size when averaging multiple cases, in accord with what has been observed in human trials. The probability of a patient harbouring a second clone in the HSC pool was found to be extremely low (~10-8). Thus our results suggest that in clinical cases of PNH where two independent clones of mutant cells are observed, only one of those is likely to have originated in the HSC pool.

The mechanisms leading to expansion of HSC with mutations in the PIG-A gene that leads to the PNH phenotype remains unclear. Data so far suggests there is no intrinsic fitness advantage of the mutant cells compared to normal cells. Assuming neutral drift within the HSC compartment, we determined from first principles the incidence of the disease in a population, the average clone size in patients, the probability of clonal extinction, the likelihood of several separate clones coexisting in the HSC pool, and the expected expansion rate of a mutant clone. Our results are similar to what is observed in clinical practice. We also find that in such a model the probability of multiple PNH clones arising independently in the HSC pool is exceptionally small. This suggests that in clinical cases where more than one distinct clone is observed, all but one of the clones are likely to have emerged in cells that are downstream of the HSC population. We propose that PNH is perhaps the first disease where neutral drift alone may be responsible for clonal expansion leading to a clinical problem.

Acute haemolytic crisis in a Thai patient with homozygous haemoglobin Constant Spring (Hb CS/CS): a case report

Acute haemolysis associated with mild upper respiratory tract infection was observed in a Thai boy who presented with a rapid decline in haemoglobin (Hb) levels, haemoglobinuria and evidence of intravascular haemolysis. Several possible causes giving rise to such a condition were excluded including G6PD deficiency, which is extremely common in Thailand. Subsequent haematological and molecular analyses demonstrated that the patient was homozygous for Hb Constant Spring (Hb CS/CS), an a globin haemoglobinopathy. It has been shown previously that patients with homozygous Hb CS had mild haemolytic anaemia secondary to an accumulation of alpha(CS) chains, which are toxic to red blood cell membrane cytoskeletons. Increased body temperature might induce more precipitation of this a globin variant. This report highlights the importance of Hb CS/CS as a potential predisposing cause of acute haemolysis in children that might be aggravated by acute bacterial or viral infections. This is particularly relevant for patients of Southeast Asian descent where this abnormal haemoglobin is highly prevalent.

Hemoglobin H disease in Guangxi province, Southern China: clinical review of 357 patients

The clinical characteristics of 357 patients with hemoglobin H (HbH) disease from the Guangxi province of Southern China were studied. One hundred and ninety-one (53.3%) patients were diagnosed with HbH-Constant Spring, 19 were diagnosed with HbH Westmead. Ten patients were shown to have coinherited HbH-Constant Spring/QS with a β-thalassemia mutation. Coinheritance of the β-thalassemia gene does not alleviate anemia (8.2 ± 2.3 vs. 7.6 ± 1.7 g/dl, p = 0.276), or influence age at diagnosis (20.2 ± 19.6 vs. 12.9 ± 11.0 years, p = 0.276). Ferritin levels were significantly higher in the group of patients with the nondeletional form of the disease (475 ± 719 vs. 249 ± 264 ng/ml, p = 0.005).

Hyperbilirubinemia in Homozygous HbE Disease Is Associated with the UGT1A1 Gene Polymorphism

Homozygous HbE [beta26(B8)Glu-->Lys] is a clinically mild disorder with no significant symptoms. However, we have frequently noted hyperbilirubinemia among patients with homozygous HbE in the Indian population, with jaundice being the major complaint at presentation. A study of the UGT1A1 gene polymorphism shows that the variant TA7 in the promoter region of the UGT1A1 gene is associated with hyperbilirubinemia in homozygous HbE patients.

Hemoglobin E disease in North Indian population: a report of 11 cases

Hemoglobin E (beta26Glu --> Lys) is the most common hemoglobin (Hb) variant in Southeast Asia and the second most prevalent worldwide. However in India, it is prevalent in Bengal and the north-eastern region, but relatively rare in the rest of the country. Identification of this Hb variant is important, because the doubly heterozygous state for HbE and beta-thalassemia is characterized clinically by thalassemia major, a situation different from other compound heterozygous states for structural beta-chain variants and beta-thalassemia. Thus, the affected individual may be symptomatic and transfusion dependent at an early age. This paper reports four cases with Hb E trait, three cases with hemoglobin E disease and another four cases with Ebeta-thalassemia. Laboratory investigations are based on RBC indices and high performance liquid chromatography (HPLC). A negative correlation has been found to exist between levels of HbA(2) and RBC indices including the MCV and MCH. A similar correlation has been seen between levels of HbF with Hb, RBC count, and MCV. The main aim is to increase the awareness of this relatively rare disorder, so that it can be included in the differential diagnosis of patients presenting clinically like thalassemia intermedia or thalassemia major. This awareness may also help in prenatal diagnosis, genetic counseling and clinical management. The clinical, hematological and laboratory features of this disorder are also discussed.

Expression of betaE and gamma-globin genes in infants heterozygous for hemoglobin E and double heterozygous for hemoglobin E and alpha-thalassemia

This study described the expression of betaE-globin in newborns heterozygous for HbE. Despite the lower level of HbE, the pattern of betaE-globin gene expression was similar to betaA-globin because the increase in HbE and HbA reached the peak level at the same time. A delayed decline of HbF was observed.

Hypomorphic promoter mutation in PIGM causes inherited glycosylphosphatidylinositol deficiency

Attachment to the plasma membrane by linkage to a glycosylphosphatidylinositol (GPI) anchor is a mode of protein expression highly conserved from protozoa to mammals. As a clinical entity, deficiency of GPI has been recognized as paroxysmal nocturnal hemoglobinuria, an acquired clonal disorder associated with somatic mutations of the X-linked PIGA gene in hematopoietic cells. We have identified a novel disease characterized by a propensity to venous thrombosis and seizures in which deficiency of GPI is inherited in an autosomal recessive manner. In two unrelated kindreds, a point mutation (c --> g) at position -270 from the start codon of PIGM, a mannosyltransferase-encoding gene, disrupts binding of the transcription factor Sp1 to its cognate promoter motif. This mutation substantially reduces transcription of PIGM and blocks mannosylation of GPI, leading to partial but severe deficiency of GPI. These findings indicate that biosynthesis of GPI is essential to maintain homeostasis of blood coagulation and neurological function.

Hyperbilirubinemia and cholelithiasis in Chinese patients with hemoglobin H disease

Hemoglobin H disease (HbH) is a hemoglobinopathy peculiar to parts of the world with high incidence alpha-thalassemia mutations. Among 90 HbH cases, 50 cases suffered from clinically significant jaundice (bilirubin >30 mmol/l), including 14 with severe jaundice (bilirubin >60 mmol/l). Cholelithiasis was found in 38 cases. The incidence is roughly eight times higher than that in background control population but 50% lower than that in beta-thalassemia. The risk of gallstones was related to higher bilirubin levels but not alpha-globin genotype, sex, ferritin, and hemoglobin levels. Homozygotes or double heterozygotes for Gilbert alleles (17.2%), but not heterozgyotes (42.2%), were found to have a significantly increased risk of gallstones and jaundice. However, common Chinese Gilbert syndrome alleles do not completely explain the variable risks.

Hb SE disease: a clinico-hematological profile

Hb S and Hb E are globally common hemoglobinopathies. However, Hb SE double heterozygous state is uncommon, with only 25 cases reported so far in literature. We present two more cases. One presented with gallstones, and the other was asymptomatic. This type of disorder was previously described as a relatively asymptomatic condition compared to HbSS. A review of the 25 reported cases in literature shows that 40.7% (11/27) of these cases are symptomatic. Gender, hematological parameters and levels of Hb S, E or F do not predict clinical severity.

Antioxidant in plasma of hemoglobin-E trait

A study of antioxidant levels among Thai subjects with a hemoglobin E trait was undertaken. The objective of this study was to determine whether the antioxidant level would be disturbed in the HbE condition. All 185 volunteer subjects, 171 normal healthy subjects and 14 HbE carriers were recruited. For each case, an antioxidant determination was performed using the Trolox equivalent antioxidant capacity (TEAC) method. According to this study, the average antioxidant level in the healthy group was 3.439 +/- 0.220 mM Trolox equivalent, and in HbE trait group was 3.276 +/- 0.209 mM Trolox equivalent. There was a significant decrease of the antioxidant level in the HbE trait group (p = 0.008).

Targeted deletion of the CD59 gene causes spontaneous intravascular hemolysis and hemoglobinuria

The glycolipid-anchored glycoprotein CD59 inhibits assembly of the lytic membrane attack complex of complement by incorporation into the forming complex. Absence of CD59 and other glycolipid-anchored molecules on circulating cells in the human hemolytic disorder paroxysmal nocturnal hemoglobinuria is associated with intravascular hemolysis and thrombosis. To examine the role of CD59 in protecting host tissues in health and disease, CD59-deficient (CD59(-/-)) mice were produced by gene targeting in embryonic stem cells. Absence of CD59 was confirmed by staining cells and tissues with specific antibody. Despite the complete absence of CD59, mice were healthy and fertile. Erythrocytes in vitro displayed increased susceptibility to complement and were positive in an acidified serum lysis test. Despite this, CD59(-/-) mice were not anemic but had elevated reticulocyte counts, indicating accelerated erythrocyte turnover. Fresh plasma and urine from CD59(-/-) mice contained increased amounts of hemoglobin when compared with littermate controls, providing further evidence for spontaneous intravascular hemolysis. Intravascular hemolysis was increased following administration of cobra venom factor to trigger complement activation. CD59(-/-) mice will provide a tool for characterizing the importance of CD59 in protection of self tissues from membrane attack complex damage in health and during diseases in which complement is activated.

Differential diagnosis of Hb EE and Hb E-beta(0)-thalassemia by protein and DNA analyses

DNA analysis was used to confirm the Hb EE genotype and to differentiate from the possible genotype of Hb E-beta(0)-thalassemia in two Malay patients. The first patient was a 13-year-old Malay girl, whose parents were available for family studies. The second patient was a 69-year-old Malay woman with no living family members. The presence of Hb E in both propositi was confirmed by: (1) its characteristic electrophoretic mobilities on alkaline/acid gels; (2) its chromatographic properties on anion/cation exchangers, and (3) its mildly insoluble properties. However, differential diagnosis of Hb EE and Hb E-beta(0)-thalassemia was challenging in these two cases. In the former, this was because of the possible interactions of the parents' phenotypes; i.e., the mother had a similar phenotype. In the latter, it was due to the lack of any living family members for family studies. In this communication, we present the protein and DNA analyses, including data on the use of the restriction enzyme Mnl I, for the definitive diagnosis of the Hb EE genotype in the propositi of these two Malay families.

Repression of aberrant splicing in human beta-globin pre-mRNA with HbE mutation by antisense oligoribonucleotide or splicing factor SF2/ASF

Hemoglobin (Hb) E is the most common Hb variant among Southeast Asian populations. The mutation in codon 26 (GAG to AAG) of the beta-globin gene (beta E) induces alternative splicing, resulting in the production of normally and aberrantly spliced beta-globin mRNA. Compound heterozygosity for beta-thalassemia and HbE, beta-thalassemia/HbE disease, could lead to a severe thalassemia phenotype. Repression of aberrant splicing from the beta E mutation could ameliorate the severity in such patients. We showed that the aberrant splicing was partially repressed in cells treated with antisense oligoribonucleotide targeted to the aberrant 5' splice site. The maximum effect of the antisense oligoribonucleotide was observed at a concentration of 0.4 mumol/L, 36 hours after the treatment in our experiment. We also analyzed the effect of the transient and stable expression of SF2/ASF on aberrant splicing in cells expressing the beta E-globin gene. Partial repression of the aberrant splicing was also observed in both expression systems. Our results imply that antisense oligoribonucleotide treatment and SF2/ASF expression are possible therapeutic applications for beta-thalassemia/HbE disease.

Hb Sallanches [alpha104(G11)Cys-->Tyr]: a rare alpha2-globin chain variant found in the homozygous state in three members of a Pakistani family

We have identified a rare alpha2-globin chain variant, Hb Sallanches [alpha104(G11) Cys-->Tyr], in a Pakistani family having three homozygous patients with transfusion-dependent Hb H disease. This variant, previously reported in a French patient and a West Indian homozygous patient with Hb H disease, is due to a mutation at codon 104 (TGC-->TAC). This is the third case of Hb Sallanches and the first case with three homozygous patients reported in Pakistan. Due to the different ethnic origins of the patients, it is very likely an independent mutation.

Phenotypic variability of Filipino beta(o)-thalassemia/HbE patients in Indonesia

Three Indonesian patients with identical genotypes, each compound heterozygotes for Filipino beta(o)-thalassemia/HbE, expressed different clinical severities. One patient has mild disease and is transfusion independent, while the other two are severely affected and transfusion dependent. The size of the Filipino beta(o)-globin gene deletion was confirmed to be 45 kb, resolving conflicting values given in the literature. Neither ameliorating genetic factors such as alpha-globin gene deletions or the XmnI restriction site polymorphism at position -158 upstream of the (G)gamma-globin gene, nor differences in beta-globin gene haplotype, explain the phenotypic variation. These observations have implications for the development of antenatal diagnosis in Indonesia, as at present it is not possible to give an accurate prediction of severity of phenotype for this common genotype.

Molecular basis of beta-thalassemia in the Maldives

We have systematically analyzed beta-thalassemia genes using polymerase chain reaction-related techniques, dot-blot hybridization with oligonucleotide probes, allele specific-polymerase chain reaction, and sequencing of amplified DNA fragments from 41 unrelated patients, including 37 beta-thalassemia homozygotes, three with beta-thalassemia/Hb E, and one with beta-thalassemia/Hb S. Four different beta-thalassemia mutations were detected in 78 alleles. These are the IVS-I-5 (G-->C), codon 30 (AGG-->ACG) [also indicated as IVS-I (-1)], IVS-I-1 (G-->A), and codons 41/42 (-TTCT) mutations. The distribution of the beta-thalassemia mutations in the Maldives is 58 alleles (74.3%) with the IVS-I-5 (G-->C) mutation, 12 (15.4%) with the codon 30 (AGG-->ACG) mutation, seven (9%) with the IVS-I-1 (G-->A) mutation, and one with the codons 41/42 (-TTCT) mutation. The first three mutations account for 98.7% of the total number of beta-thalassemia chromosomes studied. These mutations are clustered in the region spanning 6 bp around the junction of exon 1 and the first intervening sequence of the beta-globin gene. These observations have significant implications for setting up a thalassemia prevention and control program in the Maldives. Analysis of haplotypes and frameworks of chromosomes bearing each beta-thalassemia mutation suggested that the origin and spread of these mutations were reflected by the historical record.

Clinical expression of a rare beta-globin gene mutation co-inherited with haemoglobin E-disease

A single nucleotide substitution and the effect on the phenotype in an Indonesian family with beta-thalassaemia, HbE-trait and HbE-beta-thalassaemia is described. In the proposita (female, age 20 (Hb 7.4 mmol/l; MCV 72 fl; MCH 1.45 fmol; HbA2 3.5%; HbF 2.4%)). An A/G mutation in the RNA cleavage and polyadenylation sequence was detected (AATAAA/AATAGA). Her sister (Hb 8.2 mmol/l; MCV 77 fl; MCH 1.60 fmol; HbA2/HbE 32.4%), carried a different mutation in the beta-globin gene (codon 25; G129/A), and consequently had HbE-trait. Their mother had a haemoglobin concentration of 6.4 mmol/l (MCV 56 fl; MCH 1.20 fmol; HbA2/HbE 55.8%). She was compound heterozygous for the mutation in the poly A-signal and HbE-trait. Using restriction enzyme analysis and linkage studies, we subsequently identified six family members with HbE-beta-thalassaemia, five with beta-thalassaemia and six with HbE-trait. Two individuals were unaffected. The mutation in the polyadenylation sequence causes a mild form of beta (+)-thalassaemia. The MCV and MCH in individuals with both beta-thalassaemia and HbE-trait were significantly lower, yet on average they were only slightly more anaemic than those carrying only the thalassaemic gene.

Interaction of hemoglobin E and pyrimidine 5' nucleotidase deficiency

A Bangladeshi family is described in which the genes for both hemoglobin E (Hb E) and pyrimidine 5' nucleotidase deficiency are segregating. An individual homozygous for both these conditions has a severe hemolytic anemia, whereas family members who are homozygous for Hb E are asymptomatic and those homozygous for pyrimidine 5' nucleotidase deficiency have the mild hemolytic anemia that is characteristic of this disorder. Globin-chain synthesis experiments have shown that the mechanism underlying the interaction between these two genotypes is a marked decrease in the stability of Hb E in pyrimidine 5' nucleotidase-deficient red blood cells (RBCs). It has also been found that in the enzyme-deficient RBCs in which Hb E is highly unstable, free alpha-chains, though not beta E-chains, acoumulate on the membrane. In view of the increasing evidence that the hemolysis associated with pyrimidine 5' nucleotidase deficiency results not only from an increase in the level of erythrocyte pyrimidines, but also from inhibition of the hexose monophosphate shunt activity in young erythrocytes, it is likely that the marked instability of Hb E in the enzyme-deficient cells results from oxidant damage acting on a mildly unstable Hb variant. These observations may have important implications for the better understanding of the pathophysiology of Hb E/beta-thalassemia, globally the commonest important form of thalassemia.

Hydroxyurea increases hemoglobin F levels and improves the effectiveness of erythropoiesis in beta-thalassemia/hemoglobin E disease

Hydroxyurea (HU) is one of several agents that have been shown to enhance hemoglobin (Hb) F levels in patients with sickle cell disease and may be useful as a therapy for beta-globinopathies. However, limited information exists on the effects of HU in patients with thalassemia. Accordingly, we examined the hematologic effects of orally administered HU in 13 patients with beta-thalassemia/Hb E, including four patients who had been splenectomized. These patients were treated with escalating doses (final range, 10 to 20 mg/kg/d) for 5 months and were observed in the outpatient hematology clinic every 2 to 4 weeks. Complete blood counts including reticulocyte counts, amounts of Hb E and Hb F, G gamma:A gamma and alpha:non-alpha globin biosynthetic ratios were evaluated before and during treatment. Almost all patients responded with an average increase of 33% in Hb F levels, from a mean (+/- SD) of 42% +/- 11% to 56% +/- 8% (P < .0001), and a reciprocal decline in the percentage of Hb E from 59% +/- 9% to 49% +/- 8% (P < .001). Reticulocytosis was decreased from a mean (+/- SD) of 18.0% +/- 15.6% to 11.7% +/- 9.1% (P < .05); there was also a slight (10%) but statistically significant increase in hemoglobin levels and an improved balance in alpha:non-alpha globin chains ratios. The side effects were minimal in most patients, although these patients tended to tolerate a lower dose of HU before significant myelosuppression than has been our previous experience in sickle cell disease. One splenectomized patient died of sepsis during the trial. We conclude that increased Hb F production in beta-thalassemia/Hb E patients, with an improvement in the alpha:non-alpha globin ratios and, probably, the effectiveness of erythropoiesis, can be achieved using HU. Longer trials of HU in this population, including at other doses and in combination with other agents, appear warranted.

Discriminant function using red cell indices to distinguish between HbC and HbE traits

Values for MCV, MCH, MCHC and red cell distribution width (RDW) derived from subjects with HbC and HbE traits using a Technicon H*1 automated blood count analyser were compared. Significantly higher MCH, MCHC and RDW values were found in those with HbC trait. By use of a simple discriminant function (MCHC2 x RDW/1000), 19/20 subjects with HbC trait gave a value > or = 16.3, and 20/21 subjects with HbE trait gave a value < or = 16.2. The function described may be of value as an adjunct to electrophoresis in intralaboratory quality control.

Acute hemolysis in glutathione peroxidase deficiency

Severe acute hemoglobinemia and hemoglobinuria developed in a 17-year-old Japanese male with no history of exposure to any oxidizing agents. Examination of erythrocyte enzyme activity revealed that the patient's erythrocyte glutathione peroxidase (GSH-Px) activity was decreased to about a half that in control cells. Serum selenium (Se) concentration was within normal limits. Family studies showed that GSH-Px activity in the erythrocytes of two siblings was similarly decreased. It was suggested that the proband was suffering from a hereditary heterozygous GSH-Px deficiency, which appeared to be associated with acute hemolysis.

Laboratory diagnosis of hemoglobinopathies

Diagnostic tests for most common hemoglobinopathies and recent advances in structural analysis of variant hemoglobins are reviewed. Routine and newly introduced methods that apply to the diagnosis of sickle cell anemia, thalassemia and the hemoglobin E disorders are presented. A brief description of the clinical course for each of these disorders is given, and potential pitfalls in diagnosis are discussed. Application of high-performance liquid chromatography and various mass spectrometric techniques (electrospray ionization mass spectrometry, liquid secondary ion mass spectrometry, and tandem mass spectrometry) for evaluation of hemoglobinopathy is presented.

[Hereditary cyanosis caused by the presence of abnormal hemoglobin M in the blood: its detection, identification and properties]

A total of 17 cases of anomalous hemoglobin M (Hb M) were detected among subjects of varying nationalities in different regions of the USSR. The methods used for identification of Hb M Saskatoon, Hb M Boston, Hb M Iwate, Hb M Hyde Park have been described, among them--electron paramagnetic resonance. Spectral characteristics, electrophoretic mobility of these Hb in pH gradient, reaction with cyanides, thermal stability, in vitro reduction with methemoglobin reductase, isolated from donor's red blood cells, have been investigated. The functional parameters (log P50 and n) have been determined for hemolysates containing anomalous hemoglobin, as well as for chromatographically pure fractions of anomalous hemoglobins. The importance of the proper diagnosis of hemoglobinosis M has been stressed.

[Hemolyzing antibodies to markers of the P blood factor system as a problem in blood transfusion and pregnancy. With reference to serology, biochemistry and genetics]

The extremely rare phenotypes p, P1k and P2k (0.0005-0.0006%) of the blood group P system are usually found in consanguinous families. In the serum of these persons haemolytic antibodies with the specificity anti-PP1Pk and anti-P are found, causing severe haemolytic reactions after transfusion of incompatible blood. Because of their rarity it is difficult to find compatible blood donors. The antibodies are also associated with abortion early in pregnancy. Since 1948 at the "Institut für Blutgruppenserologie der Universität Wien" 4 persons of the phenotype p and 3 of the type P2k were observed in altogether 5 families. Two of them needed blood transfusions, the one p patient received p blood from her sister, who likewise gave blood to the other p patient. This latter patient additionally received three blood units which had been stored in liquid nitrogen and came from Austria and from the European bank of frozen blood in Amsterdam (Council of Europe). The pedigrees of three families with 5 probands out of the 7 observed cases could be reconstructed and showed consanguinity, partly some generations back. A genetic model valid at the moment for the biosynthetic pathway of the P antigens is demonstrated and the appropriate serological characteristics of the haemolytic antibodies are shown. The seven antibodies are partly IgG and partly IgM antibodies, optimally reacting using the indirect antiglobulin test or enzyme-treated red cells. The range of the antibody titres was between 1:8 and 1:1024. Absorption of Anti-PP1Pk sera with red cells of type P1 to get Anti-Pk and inhibition with hydatidcyst fluid and globoside to receive Anti-P and Anti-P1 + Pk, respectively were partly successful.

The hemoglobin E belt at the Thailand-Kampuchea border: ethnic and environmental determinants of hemoglobin E and beta-thalassemia gene frequencies

The frequencies of the hemoglobin E gene (HBB*E) and the beta-thalassemia gene(s) (HBB*T) were determined in 890 healthy adult males from three areas at the Thai-Kampuchean border in Northeastern Thailand. The population of the three study areas differs ethnically: area I is inhabited by Khmer-speaking people, area II has an ethnically mixed population (Tai-Lao, Soui and Khmer), and area III is predominantly Lao. In view of the topographic differences in malaria endemicity in the pre-eradication era, the probands from the three study areas were divided into subgroups "hills" and "plains" according to the location of their home villages. The frequencies of HBB*T were generally low, but the difference between the HBB*E frequencies in the "hills" (0.3295) and "plains" (0.2455) subgroups was highly significant. This is interpreted as environmental effect due to selection by malaria. A "hemoglobin E belt" with HBB*E frequencies between 0.3 and 0.35 extends along the Dangraek mountain chain at the border between Thailand and Kampuchea.

Concomitant inheritance of alpha-thalassemia in beta 0- thalassemia/Hb E disease

Concomitant inheritance of alpha-thalassemia in patients with beta 0-thalassemia/hemoglobin (Hb) E disease was detected by restriction endonuclease DNA mapping. Among 42 patients with beta 0-thalassemia/Hb E disease, seven were found to have an alpha-thalassemia-2 haplotype. Of these, five belonged to the rightward or 3.7-kb type of alpha-thalassemia-2 and the remaining two the leftward or 4.2-kb type. All the seven patients with alpha-thalassemia-2 haplotype had hemoglobin levels of 7.4 g/dl or above; those without detectable alpha-thalassemia had hemoglobin levels both higher and lower than 7.4 g/dl. The latter attended the clinic regularly, the former did occasionally. These findings suggest that concomitant inheritance of alpha-thalassemia can alleviate the severity of beta 0-thalassemia/Hb E disease. Failure to find alpha-thalassemia-1 haplotype in these patients suggests that concomitant inheritance of alpha-thalassemia-1 with beta 0-thalassemia/Hb E might lead to so mild a condition that the individuals do not present clinically. The fact that many patients without a detectable alpha-thalassemia haplotype also had hemoglobin levels of 7.4 g/dl or higher suggests that there are additional factors responsible for the mildness of beta 0-thalassemia/Hb E disease.

The molecular basis of alpha-thalassaemia in Thailand

The molecular basis of alpha-thalassaemia has been established in 48 Thai subjects with Hb H disease and 15 with the Hb Bart's hydrops fetalis syndrome. This study has shown that in this population there are at least 18 different types of chromosome carrying seven independent alpha-thalassaemia mutations one of which is a novel deletion removing the entire alpha-globin gene complex. Although there are a limited number of alpha-thalassaemia determinants in the Thai population, there is a remarkable degree of variation in the genetic markers which flank them. These markers may be of value in establishing the evolutionary history of the alpha-thalassaemias.

Hemoglobinuria after fraternity hazing

We describe a 19-year-old male who presented with traumatic hemoglobinuria. We hypothesize that this patient has a genetic haptoglobin variant with a low hemoglobin binding capacity which resulted in hemoglobinuria after physical fraternity hazing. A review of the literature regarding traumatic hemoglobinuria supports the association between decreased baseline plasma haptoglobin levels and hemoglobinuria after trauma.

The varied arrangement of the alpha globin genes in alpha thalassemia and Hb H disease in American blacks

Both Eco RI and Eco RI x Bam HI restriction endonuclease digests of DNA from black Americans with alpha thalassemia yielded an alpha-specific fragment 4 kb shorter than in normals. In Hb H disease, only the shorter fragment was noted, while in "silent carriers" (alpha-thal 2 trait), both the normal and shorter fragments were detected. One subject with single gene deletions on both homologous chromosomes (alpha-thal 1 phe. A non-deletional form of alpha thalassemia also was discovered.

Double heterozygosis for hemoglobin C-beta thalassemia: description of a Spanish family. Hemoglobin C-beta thalassemia in a Spanish family

A spanish family is described with two abnormal genes: 1) hemoglobin C in heterozygosis with normal hemoglobin, introduced by the subject's mother, and 2) heterozygotic betathalassemia for which the father is a carrier. In the subject and his sister, both abnormal genes coincide with the presence of hemoglobin C and hemoglobin F, simulating homozygosis for hemoglobin C. The clinical condition shows medium intensity chronic hemolysis. In the subject's brother, mother and grandmother, simple heterozygosis of hemoglobins A-C is seen, with no apparent clinical manifestations. The father shows subjaundice with some acute hemolytic episodes. Hypotheses are discussed which might explain the presence of these hemoglobins in Spain.