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PubMed1993

Alpha-thalassemia in the four major aboriginal groups in Taiwan.

A total of 1309 unrelated blood samples from four major Taiwan aboriginal groups, including 522 of the Ami, 246 of the Bunun, 227 of the Atayal, and 214 of the Paiwan groups, were collected. Subjects with a mean corpuscular volume below 85 fl and Hb A2 values below 3.5% were further studied with Southern hybridization to determine the status of alpha-globin genes. In the Ami, 43 (4.1%) chromosomes had alpha-thalassemia 1 and 43 (4.1%) had alpha-thalassemia 2. Of the 43 alpha-thalassemia 1 chromosomes, 33 were of the Thailand, one of the Philippine, and nine of the Southeast Asian deletion. Of the 43 alpha-thalassemia 2 chromosomes, 42 were of the type I rightward deletion and one was of leftward deletion. In the Bunun group, one chromosome (0.2%) was of the Thailand deletion and two (0.4%) were of type I rightward deletion. In the Atayal group, only one chromosome (0.2%) was of the Philippine deletion. In the Paiwan group, four chromosomes (0.9%) were of the Southeast Asian deletion and three (0.7%) were of the Thailand deletion. Among the four groups, the Ami had the highest prevalence of alpha-thalassemia, which was also higher than that of the Chinese living in Taiwan.

Blotting, Southern↗

PubMed1984

Alpha-globin gene deletion causes alpha-thalassemia syndromes in two German families.

Restriction endonuclease mapping of chromosomal DNA has been used to determine whether the alpha-globin gene deletion or non-deletion form of alpha-thalassemia is the underlying molecular defect in individuals of two unrelated German families with alpha-thalassemia syndromes. The obtained DNA pattern in all cases indicated loss of alpha-globin genes resulting in -alpha/alpha alpha, --/alpha alpha, and --/-alpha genotypes in alpha-thalassemia-2, alpha-thalassemia-1, and Hb H individuals respectively. The chromosomes showing loss of one alpha-globin gene in alpha-thalassemia-2 and Hb H disease were characterized by the so-called rightward deletion form exhibiting loss of a 3.7 kb DNA fragment in the alpha-gene cluster.

Chromosome Deletion↗

PubMed1982

The clinical phenotype of beta and delta beta thalassemias in Greece.

Based on precise evaluation of hematological findings and clinical manifestations, the relationship between genotype and clinical phenotype was studied in 475 Greek patients with beta and delta beta thalassemias. Almost all known genotypes are included in this series, but the most frequent was homozygous beta th high A2 (71.6%), beta th/beta th silent (7.4%), beta th/delta beta oth high F (6.3%) and beta th/beta th Dutch (6.3%). In general, the phenotype was related to the genotype, though clinical heterogeneity was detected among patients with the same genotype. The severe type of thalassemia major was most commonly found in homozygous beta th patients mainly of beta o/beta o and beta o/beta + genotypes while homozygous beta + patients had milder clinical manifestation. Furthermore a small group of patients, characterized as homozygous beta ++ (HbF less than 30%) had mild thalassemia intermedia. In addition mild thalassemia intermedia was principally related with homozygous delta beta oth, and compound heterozygous beta th/beta th silent I, and less frequently with other genotypes such as compound heterozygous with beta th/beta th Dutch, beta th/beta th silent II, beta th/delta beta oth high F or Lepore. It was shown that precise genetic characterization and clinical evaluation is of primary importance in predicting the prognosis and formulating the proper treatment for the individual patient with thalassemia.

Child↗

PubMed1980

The unreliability of mean corpuscular volume and mean cellular hemoglobin determinations in the diagnosis of alpha-thalassemia in newborn infants.

Mean corpuscular volume (MCV) and mean cellular hemoglobin (MCH) were determined by means of a Hemalog 8/90 electronic counter in 51 full-term newborn infants with alpha-thalassemia-2 and 15 with alpha-thalassemia-1, as well as in 150 normal newborn infants. The mean MCV and MCH values were 92 fl +/- 06 and 33.26 pg +/- 2.22 in the normal newborn infants, 82 fl +/- 07 and 29.40 pg +/- 2.60 in the alpha-thalassemia-2 subjects, and 73 fl +/- 06 and 26.7 +/- 2.05 in the alpha-thalassemia-1 subjects. Four of the 150 normal newborn infants had MCV's < 79 fl and MCH's < 29.00 pg whereas 5 of the alpha-thalassemic subjects had MCV's > 90 fl and MCH's > 32.00 pg. We conclude that MCV and MCH determinations are unreliable in the diagnosis of alpha-thalassemia in the neonatal period.

Erythrocyte Indices↗

PubMed1983

beta+-Thalassemia intermedia with low HbF.

Two cases of homozygous beta+-thalassemia intermedia have been detected in a Brazilian family of Portuguese and German extraction. The patients are 39 and 43 years old, showed a normal somatic and sexual development and had been transfused only occasionally. Red blood cell morphology was similar to that of thalassemia major, but they had unusually low levels of HbF (5.0% and 6.8%). Globin chain synthesis measured in reticulocytes was in the same range as other beta-thalassemia homozygotes. One or both genes in this family must be a particularly mild beta-thalassemia allele, despite the fact that the heterozygote members of the family presented clinical, hematological, and biochemical features indistinguishable from the typical heterozygotes for the beta-thalassemia trait with high HbA2.

Adult↗

PubMed1995

Clinical heterogeneity of silent-gene b-thalassemia among Indians.

This paper describes six Indian families in which silent-gene beta-thalassemia was encountered by us in the past 2 years. This stresses the importance of globin-chain synthesis in the diagnosis of beta-thalassemia. Of these six cases, five were diagnosed retrospectively when they had a homozygous beta-thalassemia offspring. The beta/alpha synthetic ratios ranged from 0.45 to 0.60. Four belong to group-I silent beta-thalassemia and two cases to group II. The severity of thalassemia major in the offspring of these silent carriers cannot be predicted.

Adult↗

PubMed2006

Modification of CYP2E1 and CYP3A4 activities in haemoglobin E-beta thalassemia patients.

OBJECTIVE: Thalassemia disease is a genetic haemoglobinopathy usually associated with an iron overload and some degree of organ impairment. The impact of the disease on the drug metabolising enzyme cytochrome P450 (CYP) is not known. CYP2E1 and CYP3A4 are responsible for the metabolism of a large number of drugs and changes in their activities may have clinical consequences. METHODS: Haemoglobin E-beta thalassemia paediatric, blood transfusion-dependent patients apparently without complications (n = 35) and healthy controls (n = 42) were recruited in this study. The ratios of plasma 6-hydroxychlorzoxazone to chlorzoxazone, and urinary 6-beta-hydroxycortisol (6beta-OHF) to cortisol were used as indices for CYP2E1 and CYP3A4 activities, respectively. Blood and plasma samples were assayed for parameters of clinical biochemistry, oxidants and antioxidants. RESULTS: There were significant increases in serum iron, protein carbonyl and lipid peroxidation in thalassemia patients, whereas there was a decrease in blood glutathione, but unchanged plasma nitric oxide metabolites. CYP2E1 activity in the patients was unchanged; however, when the patients were stratified by splenectomy status, CYP2E1 activity was increased in non-splenectomised patients in comparison with the controls and splenectomised subjects. On the other hand, 6beta-OHF/cortisol ratios increased markedly in patients associated with depressed growth hormone levels. There were no correlations between CYP2E1 activity and oxidant stress or antioxidant parameters. CONCLUSIONS: This report is the first demonstration that thalassemia major is associated with an alteration of CYP2E1 and CYP3A4 activities; this could modify the sensitivity of thalassemia patients to the toxic or therapeutic effects of drugs.

Antioxidants↗

PubMed2003

Antierythropoietin antibodies in thalassemia patients.

We evaluated sera from 58 thalassemic patients for the presence of antierythropoietin antibodies to investigate whether these autoantibodies may relate with modest response to treatment with recombinant human erythropoietin (rhEpo). Thirty-seven patients had beta-thalassemia major, 9 patients had beta-thalassemia intermedia, and 12 patients had sickle/beta(+)-thalassemia. Of 58 patients, 24 were on rhEpo treatment in order to increase the intervals between transfusions or the hemoglobin (Hb) values. The study population was divided into three groups according to rhEpo treatment. Group A consisted of 15 patients who were on rhEpo treatment (400-600 IU/kg three times per week, subcutaneously) showing an increase of Hb values or reduction of transfusion requirements. Group B included 9 patients who did not respond to rhEpo and group C consisted of 34 patients who did not receive rhEpo. Laboratory studies included a complete blood count, measurement of serum erythropoietin, immunological evaluation, and determination of antierythropoietin antibodies using enzyme-linked immunosorbent assay (ELISA). There were no significant differences among groups A, B, and C concerning age, Hb, and endogenous erythropoietin values. Fifteen patients had positive antinuclear antibodies and three patients had positive rheumatoid factor. Antierythropoietin antibodies were detected in the sera of seven patients (five men and two women) who received rhEpo. The male patients and one female patient had no response to rhEpo while the other female patient showed response when the dose increased. Other autoantibodies seem to have no clinical significance. In the present study, we detected for the first time in thalassemia patients the presence of antierythropoietin antibodies, which may contribute to rhEpo resistance. Thalassemia patients with low response rates to rhEpo should be evaluated for the presence of antierythropoietin antibodies.

Adolescent↗

PubMed1999

Imaging features of thalassemia.

Thalassemia is a kind of chronic, inherited, microcytic anemia characterized by defective hemoglobin synthesis and ineffective erythropoiesis. In all thalassemias clinical features that result from anemia, transfusional, and absorptive iron overload are similar but vary in severity. The radiographic features of beta-thalassemia are due in large part to marrow hyperplasia. Markedly expanded marrow space lead to various skeletal manifestations including spine, skull, facial bones, and ribs. Extramedullary hematopoiesis (ExmH), hemosiderosis, and cholelithiasis are among the non-skeletal manifestations of thalassemia. The skeletal X-ray findings show characteristics of chronic overactivity of the marrow. In this article both skeletal and non-skeletal manifestations of thalassemia are discussed with an overview of X-ray findings, including MRI and CT findings.

Adrenal Glands↗

PubMed2003

Pulsed Doppler tissue imaging and myocardial function in thalassemia major.

Few studies are available on left ventricular diastolic function in beta-thalassemia major, and these have conflicting results. Our aim in this study was to analyze myocardial systolic and diastolic functions in patients with beta-thalassemia major using, for the first time, pulsed Doppler tissue imaging (DTI), and compare data with standard Doppler echocardiography. We studied 30 young patients with beta-thalassemia major (age </=16 years) with normal left ventricular systolic function and in 30 age and sex-matched controls using pulsed DTI, and compared the data with standard data obtained with Doppler echocardiography. In the beta-thalassemia major group before transfusion, early (E) and late (A) peak diastolic flow velocities were increased when compared with controls ( P = 0.0032 and P = 0.0039, respectively). The E/A ratio did not differ between the groups. All DTI parameters in the patients were similar to those of controls, except for lateral annulus ejection time adjusted for heart rate, that was significantly reduced when compared with healthy subjects ( P < 0.01). Multivariate analysis showed that ejection time adjusted for heart rate, has a significant relation with only E peak velocity ( P < 0.01) and left atrial size ( P < 0.01), two volume-dependent parameters. Our study shows that pulsed DTI parameters and standard Doppler left ventricular filling pattern in young beta-thalassemia major patients with normal left ventricular systolic function are similar to those seen in conditions of increased preload.

Adult↗

PubMed1998

The 3' breakpoint of the yunnanese (Agammadeltabeta)0-thalassemia deletion lies in an L1 family sequence: implications for the mechanism of deletion and the reactivation of the Ggamma-globin gene.

We have cloned the junction region of the previously characterized Yunnanese (Agammadeltabeta)0-thalassemia deletion and the normal DNA region surrounding its 3' breakpoint. The sequence of 1138 bp of the 3'-flanking region and 555 bp of the normal region surrounding the 3' breakpoint was determined. The 5' breakpoint of the deletion is positioned between 116 and 117 bp upstream of the Agamma-globin gene, and the 3' breakpoint at 34 bp downstream of the BglII site that lies approximately 12.7 kb upstream of the 3' deletion breakpoint of Chinese (Agammadeltabeta)0-thalassemia. There is no significant homology between the normal DNAs flanking the 5' and 3' breakpoints, except 2-bp (TG) identity and two pairs of short direct repeats at the deletion junction. The 3' breakpoint is within an L1 family sequence that normally occurs about 66 kb downstream of the beta-globin gene in 11p15. This L1 element is partially in reversed orientation at the 5' side and is therefore, presumably, an inactive element. This type of junction indicates illegitimate DNA breakage and end-joining involving the L1 sequence. Similar to many other deletions in the beta-globin locus, the Yunnanese (Agammadeltabeta)0-thalassemia deletion lacks a sequence characteristic of defined recombination factors near the deletion junction, suggesting that chromatin configuration and other locus-specific features are important. Computer-aided analysis revealed that several transcriptional factors could bind to putative motifs present in the 3'-flanking sequence. It is possible that binding features of the distal L1 element are required to generate a suitable chromatin configuration for the recombination event in Yunnanese (Agammadeltabeta)0-thalassemia. This may also be related to the reactivation of the Ggamma-globin gene in adults with the Yunnanese (Agammadeltabeta)0-thalassemia mutation.

Adult↗

PubMed2005

Comparing knowledge of beta-thalassemia in samples of Italians, Italian-Americans, and non-Italian-Americans.

The purpose of this study was to determine the level of beta-thalassemia awareness among Italians living on the eastern side of Sicily (Bronte, Catania, and Tortorici, Messina), Italian-Americans, and Americans of other ethnic backgrounds (Other-Americans). A questionnaire was developed which asked respondents knowledge questions about both beta-thalassemia and Down Syndrome. Five hundred questionnaires were distributed, and 456 were ultimately returned and analyzed (150 Italians, 156 Italian-Americans, 150 Other-Americans). Italians answered an average of 55% of the beta-thalassemia correctly compared to scores of 17 and 24% for the Italian-Americans and Other-Americans, respectively. The groups did not differ in their knowledge of Down Syndrome (all answered between 58 and 60% of the questions correctly on average). Over 80% of the Italian respondents had heard of beta-thalassemia compared to only 19% of the Italian-Americans. beta-Thalassemia education programs in Italy appear to have dramatically increased awareness of the disorder. Similar programs need to be developed for at-risk populations in the United States.

Adolescent↗

PubMed1982

Preclinical abnormal segmental cardiac manifestations of thalassemia major in children on transfusion-chelation therapy: echographic alterations of left ventricular posterior wall contraction and relaxation patterns.

The purpose of this study was to evaluate young asymptomatic patients with thalassemia major by utilizing an echocardiographic technique which traces an expanded image of the left ventricular posterior wall (LVPW). This technique separates global cardiac function from segmental changes in LV free wall thickness during systole and diastole. The study population consisted of 13 patients aged 2 to 15 years with classical homozygous beta-thalassemia. Thirty-one normal healthy individuals age 4 to 13 years served as controls. Echocardiograms, height, weight, and blood pressure were measured in all patients at their lowest hemoglobin level. Traces of the expanded LVPW were analyzed and measured; while total net thickening relative to baseline was similar in both groups at all times during systole and diastole, the LVPW in children with thalassemia was statistically thinner than in controls (p less than 0.001). Contraction was a nearly linear process in controls, but for patients with thalassemia, it was significantly faster at 50% and 75% of systolic time (p less than 0.05). Relaxation, on the other hand, was not linear for either controls or thalassemic patients. In both groups, diastolic thinning was biphasic; however, LV walls of thalassemic children thinned more slowly than normal for each time point in diastole (p less than 0.001). These results demonstrate that young children with thalassemia major, even if kept at strict transfusion and chelation regimens, have defects in LV segmental wall motion which antedate the appearance of clinical symptoms.

Adolescent↗

PubMed1978

Variability in the amount of beta-globin mRNA in beta0 thalassemia.

Globin mRNA isolated from a number of beta0 thalassemia patients of different ethnic origins was analyzed by RNA-cDNA hybridization and, in two cases, by fingerprint analysis of 125I-labeled mRNA. Quantitation of the relative amounts of alpha- and beta-mRNA by hybridization to purified alpha-and beta-cDNA revealed that in approximately half the cases, there was less than 1% as much beta-mRNA as alpha-mRNA. In the rest of the cases, low levels of beta-like mRNA were detected in amounts 4-12% as abundant as alpha-mRNA. There was variability in the yield of beta-like mRNA in patients of the same racial group, in the same patient at different times and in similarly affected siblings: beta-mRNA was virtually absent in some samples, whereas low but significant levels were found in other samples. In one patient, beta-like mRNA was not detected in peripheral blood RNA, but was present in the RNA of bone marrow cells. In one case, the thermal stability of the beta0 thalassemia mRNA-beta-cDNA hybrid was measured and found to be slightly lower than that of the authentic beta-mRNA-beta-cDNA hybrid. In none of the cases tested was there synthesis of beta-globin chains directed by beta0 thalassemia mRNA in a cell-free protein-synthesizing system, even when beta-like mRNA was detected in the sample by hybridization assays. mRNA from two patients was labeled in vitro with 125I, digested with T1 RNAase and fractionated in two dimensions. Analysis of the resulting fingerprints revealed the presence of prominent alpha chain-specific oligonucleotides without detectable beta chain-specific oligonucleotides, and thereby confirmed the results of hybridization assays showing absent or very low levels of beta-mRNA in the same RNA samples. Our results support the concept that beta0 thalassemia is heterogeneous in its molecular basis even within the same racial group: in some patients, it is associated with absent beta globin mRNA, whereas in other patients, it is associated with low but significant levels of nonfunctional beta or beta-like globin mRNA. The variable amounts of beta-like mRNA detected in different samples from the same patient, and in patients with the same genotype, indicate that as yet undefined factors can influence the yield of beta-like mRNA observed in beta0 thalassemia.

Blood Cells↗

PubMed1995

Bone minerals in beta-thalassemia minor.

Homozygous beta-thalassemia is a severe hereditary disorder associated with osteopenia. Recently it was suggested that thalassemia minor may be a risk factor for osteoporosis. The purpose of the present study was to investigate this suggestion. Bone mineral status was assessed in 22 premenopausal women and 21 men with beta-thalassemia minor. In vivo neutron activation analysis was applied to measure hand-bone phosphorus (HBP), single-photon absorptiometry to measure forearm bone mineral content (BMC), and dual-energy X-ray absorptiometry to measure spinal bone mineral density (BMD). Comparison of the HBP, BMC, and BMD values with those of sex- and age-matched healthy subjects without the beta-thalassemia trait failed to indicate a statistically significant difference for either sex group. Concerning the biochemical markers of bone metabolism that were studied (serum calcium, phosphate, alkaline phosphatase, osteocalcin, and parathyroid hormone, and 3-h fasting urine calcium-to-urine creatinine ratio) no difference was observed between the study subjects and matched controls. In conclusion, the present study showed that subjects with beta-thalassemia minor are not at risk for osteoporosis.

Absorptiometry, Photon↗

PubMed2006

Outcomes of transplantation with related- and unrelated-donor stem cells in children with severe thalassemia.

Recently published reports indicate that the outcome of unrelated donor transplantations in patients with leukemia is currently comparable to that of transplantation from identical family donors. We investigated the possibly favorable outcomes of related and unrelated transplantation in children with severe thalassemia. We reviewed transplantation outcome in 49 consecutive children with severe thalassemia who underwent allogeneic stem cell transplantation with related-donor (n=28) and unrelated-donor (n=21) stem cells between September 1992 and May 2005 at the Faculty of Medicine, Ramathibodi Hospital, Mahidol University (Bangkok, Thailand). Analysis of engraftment, frequency of procedure-related complications, and thalassemia-free survival showed no advantage from use of related-donor stem cells. The 2-year thalassemia-free survival estimate for recipients of related-donor stem cells was 82% compared with 71% in the unrelated-donor stem cell group (P=.42). The present study provides evidence to support the view that it is quite reasonable to consider unrelated-donor stem cell transplantation an acceptable therapeutic approach in severe thalassemia, at least for patients who are not fully compliant with conventional treatment and do not yet show irreversible severe complications of iron overload.

Adolescent↗

PubMed2006

Prevalence of -alpha(3.7) and alpha alpha alpha(anti3.7) alleles in sickle cell trait and beta-thalassemia patients in Mexico.

The aim of this study was to determine the frequency of alpha-globin gene mutations in three groups of Mexican unrelated individuals. The first two groups were normal and sickle cell trait individuals from the Costa Chica region, a place with a 12.8% frequency of HbS carriers, and the third group comprised of Mexican mestizo patients with beta-thalassemia. We searched for -alpha(3.7) and -alpha(4.2) alpha(+)-thalassemia deletion alleles, as well as the alpha alpha alpha(anti3.7) triplication through long-gap PCR. The alleles -alpha(3.7) and alpha alpha alpha(anti3.7) were found in the heterozygote state only; 19% of the normal subjects had the -alpha(3.7) allele, and 2% showed the alpha alpha alpha(anti3.7) allele. In individuals with the sickle cell trait, 17% had the -alpha(3.7) deletion, and the alpha alpha alpha(anti3.7) triplication was observed in 3% of these individuals. We revealed that 16% of the subjects with beta-thalassemia showed the -alpha(3.7) deletion and 28% the alpha alpha alpha(anti3.7) triplication. The -alpha(4.2) deletion was not detected in any individual. The frequency of the -alpha(3.7) allele was roughly the same in the three groups studied; this can be explained by the fact that the three groups have common genes from Africa and the Mediterranean, where a high prevalence of alpha(+)-thalassemia has been observed. To our knowledge, the frequency of alpha alpha alpha(anti3.7) triplication observed in the Mexican beta-thalassemia patients is the highest reported. As the -alpha(3.7) and alpha alpha alpha(anti3.7) alleles are very common in our selected populations, we believe that there is a need to investigate systematically the alpha-globin gene mutations in all hemoglobinopathies in the Mexican population.

Alleles↗

PubMed2004

Hematopoietic stem cell transplantation for beta-thalassemia major: experience in south of Iran.

INTRODUCTION: Allogeneic stem cell transplantation as a curative treatment for thalassemia major was established in Shiraz in 1993. In this article we describe our results of 10 years experience with allogeneic bone marrow transplantation for thalassemia major. METHODS: From June 1993 to January 2003, 112 cases of beta-thalassemia major underwent allogeneic marrow transplantation from HLA-identical or one antigen-mismatched related donors. Conditioning chemotherapy included busulfan (14 to 15 mg/kg), cyclophosphamide (200 mg/kg), and antithymocyte globulin (ATG; 40 mg/kg). Prophylaxis for graft-versus-host disease consisted of cyclosporine, prednisolone, and methotrexate. RESULTS: One hundred twelve patients with a diagnosis of beta-thalassemia major underwent allogeneic marrow transplantation during this period. The mean age of the patients was 9.5 years with the range of 2 to 20 years. The distribution of cases according to the Lucarelli classification were: 27 cases class I, 38 cases class II, and 47 cases class III. Eighty-seven of 112 patients (77.6%) with diagnosis of beta-thalassemia major are living with full engraftment at a median follow-up of 6 years (range 2 to 119 months). CONCLUSION: Allogeneic bone marrow transplantation has changed the outcome of disease dramatically. According to our results stem cell transplantation is the treatment of choice for class I and II (Lucarelli risk groups). Also, we recommend transplantation as a curative method for treatment of class III beta-thalassemic patients.

Adolescent↗