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PubMed1987

Molecular basis for nondeletion alpha-thalassemia in American blacks. Alpha 2(116GAG----UAG).

An American black woman was found to have the phenotype of moderately severe alpha-thalassemia normally associated with the loss of two to three alpha-globin genes despite an alpha-globin gene map that demonstrated the loss of only a single alpha-globin gene (-alpha/alpha alpha). Several individuals in her kindred with normal alpha-globin gene mapping studies (alpha alpha/alpha alpha) had mild alpha-thalassemia hematologic values consistent with the loss of one to two alpha-globin genes. These data suggested the presence of a nondeletion alpha-thalassemia defect in this family which segregates with the intact alpha alpha gene cluster. An abnormally migrating and highly unstable alpha-globin gene product was demonstrated by in vitro translation of the reticulocyte mRNA from the proposita and this mutant alpha-globin protein was mapped to the alpha 2-globin gene by hybrid-selected translation. The abnormal alpha 2-globin gene was cloned and sequenced. A single base mutation that results in a premature termination codon was identified at codon 116 (GAG----UAG). The defined alpha-globin genotype of the proposita (-alpha/alpha 116UAG alpha) and the positioning of this nonsense mutation at the alpha 2-globin gene locus are fully consistent with the observed alpha-thalassemia phenotype.

Aged↗
PubMed2003

Silent stroke in a case of beta-thalassemia major associated with chronic renal failure and diabetes mellitus.

Severe anemia, growth retardation, diabetes mellitus, cardiac disorders, and, infrequently, stroke are well-known complications of thalassemia major. We report a girl, age 7 years, 2 months, with beta-thalassemia major associated with chronic renal failure, diabetes mellitus, and cardiomyopathy in whom a silent stroke was noted during follow-up. She was diagnosed with thalassemia major at age 6 months, chronic renal failure at age 3 years, 3 months, and diabetes mellitus and cardiomyopathy at age 7 years. Although cranial computed tomography was found to be normal at the age of 3 years, 3 months, magnetic resonance imaging showed cerebral infarct in the right frontal region at 7 years, 2 months. A thrombophilic panel revealed increased factor VIII and decreased protein C concentrations. She died from disseminated intravascular coagulation at age 7 years, 9 months. We did not record any clinical findings of stroke during her follow-up. We think that diabetes mellitus, dilated cardiomyopathy, and increased factor VIII and decreased protein C concentrations led to the occurrence of cerebral infarct. In conclusion, we emphasize that children with thalassemia major should be monitored closely for stroke. We also suggest that stroke can show a silent progression in severely affected children, as in our case.

Child↗
PubMed2002

Related umbilical cord blood transplantation in patients with thalassemia and sickle cell disease.

Allogeneic bone marrow transplantation (BMT) from HLA-identical siblings is an accepted treatment for both thalassemia and sickle cell disease (SCD). However, it is associated with decided risk of both transplant-related mortality (TRM) and chronic graft-versus-host disease (GVHD). We analyzed 44 patients (median age, 5 years; range, 1-20 years) given an allogeneic related cord blood transplant for either thalassemia (n = 33) or SCD (n = 11). Thirty children were given cyclosporin A (CsA) alone as GVHD prophylaxis, 10 received CsA and methotrexate (MTX), and 4 patients received other combinations of immunosuppressive drugs. The median number of nucleated cells infused was 4.0 x 10(7)/kg (range, 1.2-10 x 10(7)/kg). No patient died and 36 of 44 children remain free of disease, with a median follow-up of 24 months (range, 4-76 months). Only one patient with SCD did not have sustained donor engraftment as compared with 7 of the 33 patients with thalassemia. Three of these 8 patients had sustained donor engraftment after BMT from the same donor. Four patients experienced grade 2 acute GVHD; only 2 of the 36 patients at risk developed limited chronic GVHD. The 2-year probability of event-free survival is 79% and 90% for patients with thalassemia and SCD, respectively. Use of MTX for GVHD prophylaxis was associated with a greater risk of treatment failure. Related CBT for hemoglobinopathies offers a good probability of success and is associated with a low risk of GVHD. Optimization of transplantation strategies could further improve these results.

Acute Disease↗
PubMed2003

Hydroxyurea can eliminate transfusion requirements in children with severe beta-thalassemia.

Hydroxyurea (HU) enhances fetal hemoglobin (Hb) production. An increase in total Hb level has been repeatedly reported during HU treatment in patients with sickle cell disease and in several patients with beta-thalassemia intermedia. Effects in patients with beta-thalassemia major are controversial. We now report a marked elevation of total Hb levels with HU that permitted regular transfusions to be stopped in 7 children with transfusion-dependent beta-thalassemia. The median follow-up was 19 +/- 3 months (range, 13-21 months). We conclude that HU can eliminate transfusional needs in children with beta-thalassemia major, which could be particularly useful in countries such as Algeria, where supplies of blood or chelating agents are limited.

Adolescent↗
PubMed2004

New approach for bone marrow transplantation in patients with class 3 thalassemia aged younger than 17 years.

When prepared for transplantation with busulfan (BU) 14 mg/kg and cyclophosphamide (CY) 120 to 160 mg/kg, patients with thalassemia in risk class 3, aged younger than 17 years, who receive transplants from HLA-identical donors, had a 30% incidence of transplant rejection with recurrence of thalassemia. This, relatively poor, outcome was ascribed to insufficient immune suppression or to inadequate eradication of the thalassemic marrow, or both. In an attempt to enhance both immune suppression and eradication of the thalassemic clones, hydroxyurea, azathioprine, and fludarabine were added to the BU and CY. This regimen, called protocol 26, was applied to 33 consecutive patients with class 3 thalassemia aged younger than 17 years and was well tolerated with 93% survival. The incidence of recurrent thalassemia after the transplantation decreased from 30% to 8%.

Adolescent↗
PubMed2004

Enhanced phagocytosis of ring-parasitized mutant erythrocytes: a common mechanism that may explain protection against falciparum malaria in sickle trait and beta-thalassemia trait.

High frequency of erythrocyte (red blood cell [RBC]) genetic disorders such as sickle cell trait, thalassemia trait, homozygous hemoglobin C (Hb-C), and glucose-6-phosphate dehydrogenase (G6PD) deficiency in regions with high incidence of Plasmodium falciparum malaria and case-control studies support the protective role of those conditions. Protection has been attributed to defective parasite growth or to enhanced removal of the parasitized RBCs. We suggested enhanced phagocytosis of rings, the early intraerythrocytic form of the parasite, as an alternative explanation for protection in G6PD deficiency. We show here that P falciparum developed similarly in normal RBCs and in sickle trait, beta- and alpha-thalassemia trait, and HbH RBCs. We also show that membrane-bound hemichromes, autologous immunoglobulin G (IgG) and complement C3c fragments, aggregated band 3, and phagocytosis by human monocytes were remarkably higher in rings developing in all mutant RBCs considered except alpha-thalassemia trait. Phagocytosis of ring-parasitized mutant RBCs was predominantly complement mediated and very similar to phagocytosis of senescent or damaged normal RBCs. Trophozoite-parasitized normal and mutant RBCs were phagocytosed similarly in all conditions examined. Enhanced phagocytosis of ring-parasitized mutant RBCs may represent the common mechanism for malaria protection in nonimmune individuals affected by widespread RBC mutations, while individuals with alpha-thalassemia trait are likely protected by a different mechanism.

Adult↗
PubMed2004

Alpha(+)-thalassemia protects African children from severe malaria.

The high frequency of alpha(+)-thalassemia in malaria-endemic regions may reflect natural selection due to protection from potentially fatal severe malaria. In Africa, bearing 90% of global malaria morbidity and mortality, this has not yet been observed. We tested this hypothesis in an unmatched case-control study among 301 Ghanaian children with severe malaria and 2107 controls (62% parasitemic). In control children, alpha(+)-thalassemia affected neither prevalence nor density of Plasmodium falciparum. However, heterozygous alpha(+)-thalassemia was observed in 32.6% of controls but in only 26.2% of cases (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.56-0.98). Protection against severe malaria was found to be pronounced comparing severe malaria patients with parasitemic controls (adjusted OR in children < 5 years of age, 0.52; 95% CI, 0.34-0.78) and to wane with age. No protective effect was discernible for homozygous children. Our findings provide evidence for natural selection of alpha(+)-thalassemia in Africa due to protection from severe malaria.

Case-Control Studies↗
PubMed2005

Keynote address: The challenge of thalassemia for the developing countries.

The thalassemias occur at some of their highest frequencies in the developing countries, particularly those of Asia. In many countries, facilities for the control of these conditions are extremely limited. Although a great deal can be done to help the situation by developing further North-South and South-South partnerships for disseminating better practice, the major problem for the future lies in the unwillingness of governments and international health agencies to accept that the thalassemias present a health burden comparable to that of other major diseases in the developing countries. However, preliminary analyses suggest that, at least in the case of Asia, this is not true. Further work of this nature, together with more detailed frequency and economic data, are required to provide solid evidence for the health burden posed by thalassemia in the developing world. Unless this is done, the large populations of patients with thalassemia in these countries will continue to be neglected.

Adolescent↗
PubMed2005

Role of alpha-hemoglobin-stabilizing protein in normal erythropoiesis and beta-thalassemia.

Hemoglobin (Hb) synthesis is coordinated by homeostatic mechanisms to limit the accumulation of free alpha or beta subunits, which are cytotoxic. Alpha hemoglobin-stabilizing protein (AHSP) is an abundant erythroid protein that specifically binds free alphaHb, stabilizes its structure, and limits its ability to participate in chemical reactions that generate reactive oxygen species. Gene ablation studies in mice demonstrate that AHSP is required for normal erythropoiesis. AHSP-null erythrocytes are short-lived, contain Hb precipitates, and exhibit signs of oxidative damage. Loss of AHSP exacerbates beta-thalassemia in mice, indicating that altered AHSP expression or function could modify thalassemia phenotypes in humans, a topic that is beginning to be explored in clinical studies. We used biochemical, spectroscopic, and crystallographic methods to examine how AHSP stabilizes alphaHb. AHSP binds the G and H helices of alphaHb on a surface that largely overlaps with the alpha1-beta1 interface of HbA. This result explains previous findings that betaHb can competitively displace AHSP from alphaHb to form HbA tetramer. Remarkably, binding of AHSP to oxygenated alphaHb induces dramatic conformational changes and converts the heme-bound iron to an oxidized hemichrome state in which all six coordinate positions are occupied. This structure limits the reactivity of heme iron, providing a mechanism by which AHSP stabilizes alphaHb. These findings suggest a biochemical pathway through which AHSP might participate in normal Hb synthesis and modulate the severity of thalassemias. Moreover, understanding how AHSP stabilizes alphaHb provides a theoretical basis for new strategies to inhibit the damaging effects of free alphaHb that accumulates in beta-thalassemia.

Animals↗
PubMed2005

Bone marrow transplantation in adults with thalassemia: Treatment and long-term follow-up.

Current regular blood transfusion programs and chelation treatment have considerably improved survival of patients with thalassemia, which resulted in a larger proportion of adult patients. However, disease- and treatment-related complications in these patients progress over time, causing severe morbidity and shortened life expectancy. Stem cell transplantation still remains the only cure currently available for patients with thalassemia. This study updates transplant outcomes in 107 adult patients with median age of 22 years (range, 17-35 years) who received bone marrow transplantation (BMT) from human leukocyte antigen (HLA)-identical related donors between 1988 and 1996 (group A) and describes the results of BMT in 15 adult patients with median age of 21 years (range, 17-31 years) who were treated with a new treatment protocol (Protocol 26) between 1997 and 2003 (group B). The probability of survival, event-free survival, nonrejection mortality, and rejection for group A patients were 66%, 62%, 37%, and 4%, respectively, with a median follow-up of 12 years (range, 8.3-16.2 years). Group B patients treated with the new protocol had some improvement in thalassemia-free survival (67%) and lower transplant-related mortality (27%) than that of previous protocols. However, transplant-related mortality in these high-risk patients remains elevated. Current myeloablative BMT in adult patients is characterized by higher transplant-related toxicity due to an advanced phase of disease. Although this new approach to transplant adult patients with a reduced-dose intensity-conditioning regimen has improved thalassemia-free survival, transplant-related mortality in these high-risk patients remains elevated.

Adolescent↗
PubMed2005

Pharmacological induction of fetal hemoglobin: Why haven't we been more successful in thalassemia?

The first studies of the pharmacological induction of fetal hemoglobin were conducted in patients with sickle cell disease and thalassemia. Although hydroxyurea was approved by the FDA for the treatment of sickle cell disease in 1996, no similar pharmacological agent(s) has been approved for the treatment of patients with thalassemic disorders. The small-scale studies of the induction of fetal hemoglobin in thalassemia have been generally disappointing. The aim of this report is to provide a critical analysis of the factors that may be responsible for our failure to develop an effective fetal hemoglobin induction therapy for patients with thalassemia. We also describe several areas for future investigation that may be critically important for the development of an effective therapy for thalassemia.

Anemia, Sickle Cell↗
PubMed2005

Quality of life in thalassemia.

Morbidity and mortality related to thalassemia have been reduced significantly with modern medical treatment, and quality of life (QOL) should now be considered an important index of effective health care. An assessment of QOL differs from other forms of medical assessment in that it focuses on the individuals' own views of their well-being and assesses other aspects of life, giving a more holistic view of well-being. There is very little published work on evaluation of QOL in thalassemia. A suitable tool should be reproducible, sensitive to the major features of the condition that affect patients' lives, and applicable in the range of different cultural, age, and social settings. Such an instrument would be valuable in evaluating new forms of treatment and in comparing health outcomes between different clinics. Two instruments have been assessed, one derived from the WHOQOL-100 questionnaire, and one designed specifically for thalassemia, which assesses psychosocial and clinical burden, as they affect adult patients, parents, and children. Further studies are required to develop and assess such tools for use in thalassemia. Another approach is to seek patients' own views of their routine treatment and the extent to which medical treatment affects QOL. Results from patient questionnaires in the United Kingdom and Cyprus are consistent in finding problems with organization of transfusions, insufficient options with chelation therapy, and poor communication. Practical measures could be taken to address these issues.

Adolescent↗
PubMed2005

Pulmonary hypertension in beta-thalassemia.

Cardiac involvement represents the leading cause of mortality in both forms of beta-thalassemia, namely, thalassemia major (TM) and thalassemia intermedia (TI), and pulmonary hypertension (PHT) is part of the cardiopulmonary complications of the disease. PHT was initially documented in a small group of TI patients with right heart failure. In a subsequent study of a large 110-patient series, aged 32.5 +/- 11.4 years, age-related PHT was encountered in nearly 60% of cases, having caused right heart failure in six of them; interestingly, all patients had preserved left ventricular systolic function. Conflicted evidence, however, existed with respect to the development of PHT in heterogeneously treated and young TM populations. To resolve this discrepancy, a recent study compared cardiac disease between two large aged-matched groups of TM (n = 131) and TI (n = 74) patients, both treated uniformly in the currently accepted manner (regular transfusion and chelation therapy in TM, absence of any particular treatment in TI); well-treated TM patients, in contrast to TI patients, did not develop PHT, while systolic left ventricular dysfunction was present only in TM cases. PHT in beta-thalassemia results from a rather complex pathophysiology, in which chronic tissue hypoxia seems to hold a key role. Although both forms of the disease share a common molecular background, the diverse severity of the genetic defect and of the resulting clinical phenotype require a different therapeutic approach. Regular lifelong therapy in TM patients eliminates chronic hypoxia, thereby preventing PHT, whereas the absence of systematic treatment in TI leads to a cascade of reactions that compensate for chronic anemia, but at the same time allow the development of PHT.

Adult↗
PubMed2005

Physiology and pathophysiology of iron cardiomyopathy in thalassemia.

Iron cardiomyopathy remains the leading cause of death in patients with thalassemia major. Magnetic resonance imaging (MRI) is ideally suited for monitoring thalassemia patients because it can detect cardiac and liver iron burdens as well as accurately measure left ventricular dimensions and function. However, patients with thalassemia have unique physiology that alters their normative data. In this article, we review the physiology and pathophysiology of thalassemic heart disease as well as the use of MRI to monitor it. Despite regular transfusions, thalassemia major patients have larger ventricular volumes, higher cardiac outputs, and lower total vascular resistances than published data for healthy control subjects; these hemodynamic findings are consistent with chronic anemia. Cardiac iron overload increases the relative risk of further dilation, arrhythmias, and decreased systolic function. However, many patients are asymptomatic despite heavy cardiac burdens. We explore possible mechanisms behind cardiac iron-function relationships and relate these mechanisms to clinical observations.

Buffers↗
PubMed2005

Genetic analysis of candidate modifier polymorphisms in Hb E-beta 0-thalassemia patients.

Hemoglobin E (Hb E)-beta-thalassemia patients display a range of clinical severities, from nearly asymptomatic to transfusion-dependent thalassemia major. Given this clinical heterogeneity, additional genetic factors modifying disease severity remain to be discovered. Association studies are being conducted to elucidate the role of genetic polymorphisms as disease severity modifiers in Hb E-beta-thalassemia patients. Using strict scoring criteria, 1060 Hb E-beta-thalassemia patients were categorized into mild, moderate, and severe groups. Taking a candidate gene approach, we found no statistically significant differences between the mild and severe patients groups in allelic or genotypic frequencies for single nucleotide polymorphisms within five genes known to influence globin gene expression and erythropoiesis.

Adolescent↗
PubMed1981

alpha-thalassemia-2 and the variability of hematological values in children with sickle cell anemia.

Seventy children homozygous for Hb S (SS) and their 111 heterozygous (AS) parents were evaluated through their erythrocytic indices, hemoglobin composition, and occasionally through in vitro Hb chain synthesis values. Three groups of SS patients and of AS parents were identified based on differences in degree of microcytosis (MCV) and (degree of hypochromia (MCH) values. The level of Hb S in the Hb S heterozygotes showed a trimodal distribution. Five SS patients had an alpha-thalassemia homozygosity (alpha(0) alpha/alpha(0) alpha; beta(s)/beta(s) which was characterized by a distinct microcytosis and hypochromia (MCV), less than or equal to 70 fl; MCH, less than or equal to 22 pp). Nine SS patients had an alpha-thalassemia heterozygosity (alpha(0)/alpha/alpha alpha; beta(s)/beta(s)) with an MCV value of 71 to 78 fl, and an MCH value of 21.3 to 26.5 pg. Four AS parents had an alpha-thalassemia-2 homozygosity with values of MCV less than or equal to 71 fl and MCH less than or equal to 23.5. The level of Hb S was less than 31%. Thirty-nine AS parents had an alpha-thalassemia-2 heterozygosity characterized by an MCV value of 72 to 79 fl, an MCH value of 23.6 to 26.5, and a level of Hb S ranging between 31.0 and 36.8%. The Hb A2 level in SS patients was significantly correlated with the RBC counts and the MCV and MCH (r = 0.38, -0.52, and -0.47, respectively). Significant correlations in AS parents were also noted between the MCV, MCH, RBC, and Hb S percentages (r = 0.62, 0.68, and -0.49, respectively). Although the data are limited, the simultaneous occurrence of an alpha-thal-2 homozygosity seems to decrease the level of Hb F in sickle cell anemia. The presence of an alpha-thal-2 heterozygosity or homozygosity together with an SS or AS condition resulted in identifiable hematologic phenotypes.

Adolescent↗
PubMed1986

Alpha-thalassemia in premature newborns.

In this study we have carried out alpha-globin gene mapping, hemoglobin (Hb) Bart's quantitation serum bilirubin, and red blood cell indices determination in a group of Sardinian appropriate for gestational age premature infants (from 32 to 35 wk gestation) in order to define the incidence in this population of the different alpha-thalassemia syndromes, their expression rate, and the correlation between the alpha-globin genotype and phenotype at this developmental stage. The gene frequencies of deletion (-alpha) and nondeletion (alpha alpha th) alpha-thalassemia were 0.29 and 0.04, respectively, and thus not different from those found in full-term newborns from the same population. The majority of premature newborns with a single alpha-globin gene deletion [(-alpha/alpha alpha) genotype] were hematologically silent. Those who manifested increased Hb Bart's (1.2 to 3.4%) had slightly reduced Hb levels (17.4 +/- 2.6 g/dl), mean corpuscular volume (102.6 +/- 6.3 fl), and mean corpuscular Hb (34.8 +/- 2.0 pg) values. Those infants with the deletion of two alpha-globin structural genes (-alpha/-alpha) showed without exception moderate amount of Hb Bart's in the 3.5-8.1% range and an obvious decrease of Hb levels (16.1 +/- 1.6 g/dl) mean corpuscular Hb (30.6 +/- 3.5 pg), and mean corpuscular volume (88.5 +/- 11.5 fl) values. The only infant with the deletion of 3 alpha-globin structural genes had 25% Hb Bart's associated with a moderate microcytic anemia at birth and developed the clinical picture of Hb H disease. Carriers of nondeletion alpha-thalassemia (alpha alpha/alpha alpha th) showed variable amount of Hb Bart's always associated with thalassemia-like red cell indices.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Mapping↗
PubMed2003

Intraoperative blood salvage during cesarean delivery in a patient with beta thalassemia intermedia.

UNLABELLED: In this case report, we report a patient with a placenta accreta and thalassemia intermedia undergoing cesarean delivery. There are no data regarding the use of cell salvage in patients with thalassemia. During the course of her surgery, she lost approximately 9000 mL of blood. Of this blood, 2250 mL of concentrated red cells were collected, washed, and returned to the patient. During processing, increased hemolysis was noted in the effluent line of the cell salvage machine, which resolved by increasing the wash volume. The patient's postoperative course was uneventful. This case would suggest that cell salvage in patients with thalassemia can be performed safely; however, further study is warranted. IMPLICATIONS: This case report details the safe administration of cell salvage in a patient with beta thalassemia undergoing cesarean delivery. Cell salvage is the collection, washing, and re-administration of blood lost during surgery. This process has not been previously reported in a patient with this type of blood disease.

Adult↗