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[Successful preimplantation genetic diagnosis for beta-thalassemia using primer extension preamplification].

OBJECTIVE: To achieve preimplantation genetic diagnosis (PGD) of the couples at risk of having children with beta-thalassemia, as an alternative to prenatal diagnosis. METHODS: Two couples carrying different thalassemia mutations of codon 41/42 and codon intervening sequence 2 position 654 received standard in vitro fertilization treatment and intracytoplasmic sperm injection, embryo biopsy and the whole genome was amplified by primer extension preamplification (PEP). Nested polymerase chain reaction was then used to amplify two mutation sites separately. Both were detected by reverse dot-blot. RESULTS: A total of 35 oocytes were retrieved from the two patients. Among them, 87% showed two pronuclei, and embryo biopsy was performed on 16 of these embryos and 25 blastomeres were obtained. The amplification efficacy was 84%. The genotype study of non-transferred and surplus embryos showed 15% of allele drop-out rate. Five embryos were transferred to the uterus of both patients. One pregnancy achieved, resulted in live healthy twin births, which confirmed the results of PGD. CONCLUSIONS: This unaffected pregnancy resulting from PGD by PEP for beta-thalassemia demonstrates that this technique can be a effective diagnostic tool for carrier couples who desire a healthy child.

Adult↗

The problem of thalassemia in Thailand.

About one per cent of the Thai population are affected with thalassemic diseases. In each year there are almost 50,000 pregnancies at risk of having an affected fetus, one fourth of which result in thalassemic newborns. Both alpha- and beta -thalassemia, including hemoglobins E and Constant Spring, are common in Thailand. Their distribution varies from region to region and among different ethnic groups. About 30-40% of the population are carriers of at least one of the abnormal genes. Thalassemias and hemoglobinopathies are common and heterogeneous in Thailand. They combine to give more than 60 thalassemic syndromes with varying clinical severity. Abnormalities can be detected in every organ system. Studies in detail into each clinical problem will lead to better management. Hematological and molecular studies on different types of thalassemia in Thailand have made it possible to give prenatal diagnosis service to those pregnancies at risk of having a thalassemic child. Sporadic services have been given in three centers. Systematic prevention and control program is being planned by the cooperation of both the public and private sectors.

Adult↗

Delta-thalassemia due to a mutation in an erythroid-specific binding protein sequence 3' to the delta-globin gene.

We have previously described a family of Northern Sardinian descent in which the propositus was affected by thalassemia major resulting from compound heterozygosity for codon 39 nonsense mutation and the beta +IVS II nt 745 mutation and in which all heterozygotes for the beta +IVS II nt 745 mutation had normal hemoglobin (Hb) A2 levels. To define the reasons for normal HbA2 levels in otherwise typical beta-thalassemia heterozygotes, we cloned and sequenced the delta-thalassemia gene in cis to the beta +IVS II nt 745 mutation. The sequence analysis showed a single nucleotide substitution (G----A) at position 69 nts (delta +69) downstream to the polyA addition site. Dot blot analysis with an oligonucleotide probe complementary to the delta +69 mutation detected this mutation in several heterozygotes for the beta +IVS II nt 745 mutation from the proband's family, but failed to show it either in a group of normal individuals of the same origin or in nonrelated heterozygotes for the beta +IVS II nt 745 mutation of the same or different descent from the proband. The delta +69 (G----A) mutation may be responsible for the low delta-globin output from the beta +IVS II nt 745 chromosome or could be a silent polymorphism not affecting the function of the delta-globin gene. The normal G at position 69 is part of a sequence very similar to the core DNA (A/T)GATA(A/G) motif (GATA box) that is a binding site for the GATA-1 protein. Gel-retardation assay has shown that a DNA fragment containing the GATA motif with the G----A at position +69 has increased binding affinity for erythroid-specific DNA binding protein(s) as compared with the wild-type sequence. These findings may suggest that the delta +69 mutation is responsible for the deficient function of the in cis delta-globin gene.

Base Sequence↗

[Prevalence and genetic profile of alpha-thalassemia in the newborn in Ivory Coast].

The authors report 525 cases of alpha-thalassemia tracked from samples of cord blood proceeded from 12,709 new-borns. With a frequency of 4.13% alpha-thalassemia was frequently in studied population. The lack of symptomatical shapes (Hemoglobin H disease and hydrops foetalis) agree the present theory about the genetic of Black African alpha-thalassemia.

Blood Protein Electrophoresis↗

Anemia, differentiating between thalassemia minor and iron deficiency.

Many of the conditions noted in examination of the blood of patients with thalassemia minor are much like those observed in patients with iron deficiency anemia. A study was made of similarities and contrasts between blood and bone marrow features in both conditions for purposes of differential diagnosis. A salient distinction is that bone marrow hemosiderin is present in normal amount in patients with thalassemia minor, but not in those with iron deficiency anemia. If therapy with iron does not restore hemoglobin values to normal, thalassemia minor is strongly suspect. Even in the latter disease, however, there may be small fluctuations in hemoglobin values, particularly in pregnancy. One must be alert to this possibility lest a slight, fleeting increase in hemoglobin be mistakenly ascribed to iron therapy.

Anemia↗

Molecular heterogeneity of beta-thalassemia in Thailand.

beta-Globin genes in 294 chromosomes of beta-thalassemia homozygotes and patients of beta-thalassemia/HbE in the northeast, the middle and the south of Thailand were analyzed by the PCR related techniques: dot blot hybridization, direct restriction assay, direct cloning and direct sequencing of the amplified DNA fragments. Twelve different mutations were detected at various frequencies. They are an A-G at-28, codon 19 (AAC-AGC), a G-T at IVS-1 nt1,a G-C at IVS-1 nt5, a C-T at IVS-2 nt654, a G addition in codons 8/9, a C deletion in codon 41, a 4 bp deletion in codons 41/42, an A addition in codons 71/72, an AAG-TAG in codon 17, a CAG-TAG in codon 26, a TAC-TAA in codon 35 and a 8 bp deletion in codons 123-125. We also developed allele specific-polymerase chain reaction to facilitate non-radioactive detection of the mutation. Origins and spread of mutations are speculated based on the results of determination of haplotypes and frameworks that are linked to the thalassemia alleles.

Base Sequence↗

[Preimplantation genetic diagnosis for beta-thalassemia using whole genome amplification].

OBJECTIVE: To achieve pregnancy with unaffected embryo using in vitro fertilization and embryo transfer (IVF-ET) and preimplantation genetic diagnosis(PGD) for the couples at risk of having children with beta-thalassemia. METHODS: A couple carrying different thalassemia mutations of codon 41/42 and codon IVS2 position 654 received standard IVF treatment and intracytoplasmic sperm injection, embryo biopsy, single cell polymerase chain reaction and DNA analyses, and only the unaffected or carrier embryos were transferred to uterus. Pregnancy confirmation, and prenatal diagnosis were done at 20 week's gestation. RESULTS: A total of 13 embryos were analyzed in the IVF cycle. PGD indicated that 2 were normal 18.1 , 3 were affected 27.3 , and 6 were carriers 54.5 ; diagnosis was not possible in 2. Three embryos were transferred to uterus on the third day after oocyte retrieval. Ultrasonography showed twin pregnancy with one blighted ovum. The prenatal diagnoses revealed that both fetuses were unaffected, one normal baby and one carrier were born. CONCLUSION: These studies represent the successful application of PGD for beta-thalassemia in China.

Adult↗

Incidence and clinical study of ectopic erythropoiesis in adult patients with thalassemia intermedia.

We carried out total body computerized tomography (CT) studies and examined the retrospective clinical data of 29 adult patients with thalassemia intermedia (TI) to evaluate the incidence, features and pathogenesis of ectopic erythropoiesis (EE), located chiefly at the paravertebral gutters in the thorax, was present in 65.5% of the patients; 15% of them had severe clinical complications. We found a clear relationship between EE development and early presentation age of thalassemia, splenectomy and the presence of 100% fetal hemoglobin. The frequent occurrence of EE suggests that CT screening of patients with thalassemia intermedia should be mandatory. We also recommend radiotherapy as a preventive measure for the clinical complications of thalassemic patients with EE.

Adolescent↗

A community-based thalassemia prevention and control model in northern Thailand.

OBJECTIVE: To describe a community-based model for prevention and control of thalassemias and haemoglobinopathies in northern Thailand. DESIGN: Operational research composed of two components. First, a model to test whether thalassemic cases and carriers could be retrospectively detected from school children. Second, a model for prevention of prospective cases of thalassemic babies among pregnant women. SETTING: Phan District of Chiang Rai Province in northern Thailand. SUBJECTS: Component one: 5,617 preschool children and 21,123 school children were screened during May and July 1997. Component two: 256 pregnant women, 16 weeks or less gestation were screened during January and December 1997. MATERIAL AND METHOD: Component one: Sub-district public health officers and school teachers were trained to use pictures and simple clinical examination to detect suspected thalassemics among preschool and school children. Suspected cases were then referred for further clinical examination and blood testing. Blood smear examination was done at the Phan Community Hospital but Hb typing lusing on electrophoresis was done at the provincial hospital. The cellulose acetate was sent for re-reading at the Department of Medical Sciences. Component two: Osmotic fragility (OF) and dichlorophenol-indolephenol (DCIP) tests were abol in pregnant women (< or = 16 weeks of gestation) in the Phan Community Hospital. If OF test was positive, Hb typing was done at a regional medical sciences center. Their spouses were also located and tested for Hb typing. Prenatal diagnosis was done and therapeutic abortion was offered, if indicated. MAIN OUTCOME MEASURES: Cases, carriers, suspected cases, Hb typing, OF and DCIP tests. RESULTS: In Component one: 26,740 children were screened of whom 893 cases were suspected. Out of those suspected, 296 (33.2%) were normal, 140 (15.6%) were diseased, and 457 (51.2%) were carriers. 56 cases had major thalassemia diseases. Their parents were counseled. Forty couples were determined to need some form of family planning and 39 (97.5%) accepted. In Component two: 256 pregnant women were screened and 56 were found to be carriers. Only 45 husbands could be located and Hb typed. Five couples were determined to require prenatal diagnosis (PND). One happened to undergo therapeutic abortion because of HIV infection in the mother without PND. Of the four who underwent PND, one was found to have a fetus with major thalassemia. However, this couple refused therapeutic abortion because of religious reasons. CONCLUSION: This study combined both prospective and retrospective approaches and can be considered successful. However, as the only available option for pregnant women with affected fetuses is therapeutic abortion, this makes it difficult to expand the program because abortion may not be acceptable in certain communities. In addition, this model requires PND and other laboratory and clinical facilities as backups. Such backups may not be available in certain settings.

Adult↗

Thalassemia: the facts and the controversies.

In the United States, we continue to struggle with and make progress in the treatment of thalassemia. As our culture becomes more diverse, we will likely see more thalassemia in our pediatric populations. Currently, all newborns in the United States are screened for hemoglobinopathies. If a newborn screen returns with large amounts of fetal hemoglobin, alpha hemoglobin, or hemoglobin E, further investigation for thalassemia takes place. This article refreshes knowledge for those not immediately familiar with the red blood cell diseases and presents ethical controversies in care. The Cooley's Anemia Foundation Web site (www.cooleysanemia.org) provides a wealth of information for those with additional interests.

Bone Marrow Transplantation↗

Portal vein thrombosis after splenectomy for beta-thalassemia major.

Portal vein thrombosis is a recognized complication after splenectomy in beta-thalassemia major due to the chronic hypercoagulable state which has been recognized to exist in childhood thalassemia and contribute to thromboembolic events. We are reporting one patient with beta-thalassemia major developed portal vein thrombosis following splenectomy.

Abdominal Pain↗

[HbD Iran-beta-thalassemia association in a Tunisian family].

A nine-year-old boy from Béjà (North-Western Tunisia) was found to have both HbD Iran and beta-thalassemia. This patient presented with anemia and slight enlargement of the spleen and had a history of acute episodes of hemolysis. Structural studies on this hemoglobin variant used several miniaturized techniques, mainly carboxy-methyl-cellulose chromatography, reverse-phase high performance liquid chromatography and manual peptide sequencing using Chang's technique. The glutamic acid in position 22 on the beta chain was found to be replaced by a glutamine, establishing the diagnosis of HbD Iran. Concomitant presence of a thalassemia trait was suggested by the finding in the index patient of microcytosis, hypochromia and increased HbA2. The family study confirmed this patient's combined heterozygous anomalies, showing the D trait in the father and the beta thalassemia trait in the mother. The same combination was found in the index patient's sister who was, however, free of clinical symptoms. The explanation of this difference in clinical expression was provided by the ADN study which disclosed deletion of an alpha gene in the girl. The resulting alpha chain deficiency counterbalanced the beta chain deficiency.

Amino Acid Sequence↗

[Genetic study on 27 children with beta-thalassemia major and their parents in Sichuan area].

OBJECTIVE: This genetic analysis on 27 children with beta-thalassemia major and their parents was performed in an attempt to elucidate the characteristics of gene mutations, and to improve the early diagnosis and prevention of this disease in Sichuan area. METHODS: The hematologic studies of beta-thalassemia included the osmotic fragility of erythrocyte determined by brine osmosis method, the HbF qualitatively determined by one minute anti-alkaline method, the HbA2 assayed by acetyl-cellulose membrane electrophoresis and eluate photometric method, and the total hemoglobin measured by the ferric-cynade method. DNA was extracted from peripheral white blood cell with standard method (phenol-chloroform extract). Multiple allele specific polymerase chain reaction (MASPCR) was used for targeted DNA amplification and gene mutation analysis. RESULTS: It was found that the most common mutants in Sichuan area were CD17 (A-->T), CD41-42 (-TTCT) and IVS II -654 (C-->T). Their percentages were 43.64%, 36.36% and 14.54%, respectively. CONCLUSION: MASPCR method is a simple, effective and inexpensive method for genetic diagnosis of beta-thalassemia major. We identified 3 most common mutants in Sichuan by using MASPCR.

Adolescent↗

Homogeneity of beta(0)-thalassemia codon 17 (A-->T) alleles in Northern Thailand using a direct DNA sequencing method.

The aim of this study was to characterize beta-globin gene micro-haplotype polymorphisms (frameworks) associated with a beta-thalassemia mutations common in Northern Thailand using a direct DNA sequencing method. A total of 11 beta-thalassemia major patients homozygous for the codon 17 (A-->T) mutation admitted to Chiang Mai University Hospital were examined. All 22 alleles were found to contain the Asian framework 3A. The homogeneity of the framework associated with the codon 17 (A-->T) mutation indicates a relatively recent origin of the codon 17 (A-->T) mutation. Similar studies in other East Asian populations may provide information concerning the origin and the migrational spread of this beta-thalassemia mutation.

Alleles↗

[Accurate and rapid prenatal diagnosis of beta-thalassemia by a multiplex primer extension and denaturing high-performance liquid chromatography technique].

OBJECTIVE: To develop a primer-extension in combination with denaturing high-performance liquid chromatography (PE-DHPLC)-based assay for prenatal diagnosis of the five most common beta-thalassemia mutations in Chinese. METHODS: The human beta-globin gene fragment was amplified by PCR, followed by a multiple PE reaction specific for each five mutations. Then the PE product mixtures were separated for genotyping of beta-globin gene mutations using fully-denaturing DHPLC analysis. RESULTS: In a blind study, prenatal diagnosis was performed on thirty-six at-risk families for beta-thalassemia major. Reverse dot blot (RDB) analysis was used to validate each result, showing an accuracy rate of 100% for PE-DHPLC in a total of 108 samples tested. Overall, by PE-DHPLC analysis, the authors could identify the genotypes involving the five mutations and normal alleles corresponding to 94.4% (102/108) and actually make final decision for prenatal diagnosis covering 97.2% (35/36). CONCLUSION: The PE-DHPLC protocol can be a simple, rapid, and highly accurate assay in the prenatal detection of common beta-thalassemia mutations.

Base Sequence↗

Erythropoietin use in a pregnant Jehovah's witness with anemia and beta-thalassemia: a case report.

BACKGROUND: Anemia in pregnancy is seen often because of iron deficiency and the "physiologic dilution" that occurs in the third trimester. Other causes include genetic conditions, such as sickle cell anemia and thalassemias. In cases not responding to iron therapy, patients occasionally require a blood transfusion to restore adequate circulating red blood cell mass. In patients belonging to the Jehovah's Witness sect, transfusion of blood products is not allowed, and treatment of anemia in pregnancy may require use of erythropoietin. CASE: A 26-year-old, African American woman belonging to the Jehovah's Witness sect presented with anemia associated with beta-thalassemia. Iron therapy and prenatal vitamins did not correct the anemia, and the patient became symptomatic, with fatigue and shortness of breath when walking. Therapy with synthetic erythropoietin corrected the anemia, and the patient had an otherwise-uncomplicated pregnancy and delivery. CONCLUSION: Synthetic erythropoietin has been used successfully in patients with renal failure and anemia. In pregnancy associated with renal failure and anemia, synthetic erythropoietin has been shown to be safe except for rare cases of hypertension. We treated anemia caused by beta-thalassemia in pregnancy with synthetic erythropoietin to avoid a transfusion in a Jehovah's Witness.

Adult↗

Hemoglobin E-beta thalassemia: factors affecting phenotype.

The phenotype of E-beta-thalassemia is affected by several genetic factors. The aim of this study was to analyze severity of E-beta-thalassemia and correlate with HbE, HbF, E/F ratios, beta-mutation and Xmn I polymorphism. Thirty cases of E-beta-thalassemia (23 with childhood onset) were studied. HbE levels were quantitated by HPLC. Xmn1 polymorphism and beta-mutations were studied by PCR-RFLP and ARMS respectively. Commonest features were pallor (100%), splenomegaly (74%), and hepatomegaly (65%), 43% (10/23) were on regular transfusions at diagnosis. One case presented with paraplegia. Patients heterozygous for Xmn I polymorphism (+/-) had later onset (>3 yrs) compared to homozygous (-/-) absence (0.5-2.8 yrs). Most (69.6%) showed beta-mutation IVS 1-5 (G-->C). Negative correlation was found between age of onset and HbE. Thus, presentation is similar to previously reported Thai cases. Heterozygosity of Xmn I polymorphism also delays disease onset. Early diagnosis facilitates appropriate management and prenatal diagnosis.

Child↗

Hemoglobin D/beta-thalassemia and beta-thalassemia major in a Saudi family.

The present report describes the clinical, hematological and molecular characteristics in a family with unique interaction between 3 different mutations discovered during routine workup for bone marrow transplantation. In this report, complete hematological and molecular studies were performed for a large Saudi family. The family consisted of parents and 9 children, which revealed that the father is compound heterozygous for hemoglobin Hb D Punjab/beta-thalassemia, the mother is a carrier for beta-thalassemia and 3 of their children are transfusion dependent beta-thalassemia. Two of the children are compound heterozygous for Hb D Punjab/beta-thalassemia like the father but with different genotype. The other 2 children have Hb D Punjab traits while 2 other children have beta-thalassemia traits. Although, compound heterozygous for Hb D/beta-thalassemia has been well described in the literature, our report emphasizes the importance of careful analysis of the electrophoresis results and the usefulness of molecular studies in premarital screening and other screening hemoglobinopathy programs.

Adolescent↗