Displaying publications 1 - 20 of 63 in total

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  1. Cappellini MD, Viprakasit V, Taher AT, Georgiev P, Kuo KHM, Coates T, et al.
    N Engl J Med, 2020 03 26;382(13):1219-1231.
    PMID: 32212518 DOI: 10.1056/NEJMoa1910182
    BACKGROUND: Patients with transfusion-dependent β-thalassemia need regular red-cell transfusions. Luspatercept, a recombinant fusion protein that binds to select transforming growth factor β superfamily ligands, may enhance erythroid maturation and reduce the transfusion burden (the total number of red-cell units transfused) in such patients.

    METHODS: In this randomized, double-blind, phase 3 trial, we assigned, in a 2:1 ratio, adults with transfusion-dependent β-thalassemia to receive best supportive care plus luspatercept (at a dose of 1.00 to 1.25 mg per kilogram of body weight) or placebo for at least 48 weeks. The primary end point was the percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval. Other efficacy end points included reductions in the transfusion burden during any 12-week interval and results of iron studies.

    RESULTS: A total of 224 patients were assigned to the luspatercept group and 112 to the placebo group. Luspatercept or placebo was administered for a median of approximately 64 weeks in both groups. The percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval was significantly greater in the luspatercept group than in the placebo group (21.4% vs. 4.5%, P<0.001). During any 12-week interval, the percentage of patients who had a reduction in transfusion burden of at least 33% was greater in the luspatercept group than in the placebo group (70.5% vs. 29.5%), as was the percentage of those who had a reduction of at least 50% (40.2% vs. 6.3%). The least-squares mean difference between the groups in serum ferritin levels at week 48 was -348 μg per liter (95% confidence interval, -517 to -179) in favor of luspatercept. Adverse events of transient bone pain, arthralgia, dizziness, hypertension, and hyperuricemia were more common with luspatercept than placebo.

    CONCLUSIONS: The percentage of patients with transfusion-dependent β-thalassemia who had a reduction in transfusion burden was significantly greater in the luspatercept group than in the placebo group, and few adverse events led to the discontinuation of treatment. (Funded by Celgene and Acceleron Pharma; BELIEVE ClinicalTrials.gov number, NCT02604433; EudraCT number, 2015-003224-31.).

    Matched MeSH terms: beta-Thalassemia/genetics
  2. Kham SK, Yin SK, Quah TC, Loong AM, Tan PL, Fraser A, et al.
    J Pediatr Hematol Oncol, 2004 Dec;26(12):817-9.
    PMID: 15591902
    DNA technology provides a new avenue to perform neonatal screening tests for single-gene diseases in populations of high frequency. Thalassemia is one of the high-frequency single-gene disorders affecting Singapore and many countries in the malaria belt. The authors explored the feasibility of using PCR-based diagnostic screening on 1,116 unselected sequential cord blood samples for neonatal screening. The cord blood samples were screened for the most common reported alpha- and beta-thalassemia mutations in each ethnic group (Chinese, Malays, and Indians) in a multiracial population. The carrier frequency for alpha-thalassemia mutations was about 6.4% in the Chinese (alpha deletions = 3.9%, alpha deletions = 2.5%), 4.8% in Malays, and 5.2% in Indians. Only alpha deletions were observed in the Chinese. The carrier frequency for beta-thalassemia mutations was 2.7% in the Chinese, 6.3% in Malays, and 0.7% in Indians. Extrapolating to the population distribution of Singapore, the authors found a higher overall expected carrier frequency for alpha- and beta-thalassemia mutations of 9% compared with a previous population study of 6% by phenotype. The highly accurate results make this molecular epidemiologic screening an ideal method to screen for and prevent severe thalassemia in high-risk populations.
    Matched MeSH terms: beta-Thalassemia/genetics*
  3. Thong MK, Rudzki Z, Hall J, Tan JA, Chan LL, Yap SF
    Hum Mutat, 1999;13(5):413.
    PMID: 10338100 DOI: 10.1002/(SICI)1098-1004(1999)13:5<413::AID-HUMU15>
    Beta-thalassemia major is one of the commonest genetic disorders in South-East Asia. The spectrum of beta-thalassemia mutations in the various ethnic sub-populations on the island of Borneo is unknown. We studied 20 Dusun children from the East Malaysian state of Sabah (North Borneo) with a severe beta-thalassemia major phenotype, using a combination of Southern analysis, polymerase chain reaction analysis and direct sequencing. We found the children to be homozygous for a large deletion, which has a 5' breakpoint at position -4279 from the cap site of the beta-globin gene (HBB) with the 3' breakpoint located in a L1 family of repetitive sequences at an unknown distance from the beta-globin gene. This was similar to a recent finding of a large deletion causing beta-thalassemia first described in unrelated beta-thalassemia heterozygotes of Filipino descent. This report describes the first 20 families with homozygosity of the deletion causing a severe phenotype. It provides the first information on the molecular epidemiology of beta-thalassemia in Sabah. This finding has implications for the population genetics and preventative strategies for beta-thalassemia major for nearly 300 million individuals in South-East Asia.
    Matched MeSH terms: beta-Thalassemia/genetics*
  4. Lai MI, Garner C, Jiang J, Silver N, Best S, Menzel S, et al.
    Twin Res Hum Genet, 2010 Dec;13(6):567-72.
    PMID: 21142933 DOI: 10.1375/twin.13.6.567
    Cytotoxic precipitation of free α-globin monomers and its production of reactive oxygen species cause red cell membrane damage that leads to anemia and eventually ineffective erythropoiesis in β-thalassemia. Alpha hemoglobin stabilizing protein (AHSP) was found to bind only to free α-globin monomers creating a stable and inert complex which remains soluble in the cytoplasm thus preventing harmful precipitations. Alpha hemoglobin stabilizing protein was shown to bind nascent α-globin monomers with transient strength before transferring α-globin to β-globin to form hemoglobin tetramer. A classical twin study would be beneficial to investigate the role of genetics and environment in the variation of alpha hemoglobin stabilizing protein expression as this knowledge will enable us to determine further investigations with regards to therapeutic interventions if alpha hemoglobin stabilizing protein is to be a therapeutic agent for β-thalassemia. This study investigates the heritability influence of alpha hemoglobin stabilizing protein expression and factors that may contribute to this. Results indicated that a major proportion of alpha hemoglobin stabilizing protein expression was influenced by genetic heritability (46%) with cis-acting factors accounting for 19% and trans-acting factors at 27%.
    Matched MeSH terms: beta-Thalassemia/genetics*
  5. Che Yaacob NS, Islam MA, Alsaleh H, Ibrahim IK, Hassan R
    Int J Hematol, 2020 Mar;111(3):352-359.
    PMID: 31894534 DOI: 10.1007/s12185-019-02806-8
    Hemoglobin (Hb) is an iron-containing metalloprotein that transports oxygen molecules from the lungs to the rest of the human body. Among the different variants of Hb, HbA1 is the most common and is composed of two alpha (αHb) and two beta globin chains (βHb) constructing a heterotetrameric protein complex (α2β2). Due to the higher number of AHSP genes, there is a tendency to produce approximately twice as much of α subunit as β subunit. Therefore, there is a chance of presenting excess α subunit leftover in human blood plasma; excess subunits subsequently bind with each other and aggregates β-thalassemia occurs due to lack of or reduced numbers of βHb subunit. Alpha-hemoglobin-stabilizing protein (AHSP) is a scavenger protein which acts as a molecular chaperon by reversibly binding with free αHb forming a complex (AHSP-αHb) that prevents aggregation and precipitation preventing deleterious effects towards developing serious human diseases including β-thalassemia. Clinical severity worsens if mutations in AHSP gene co-occur in patients with β-thalassemia. Considering the mechanism of action of AHSP and its contribution to ameliorating β-thalassemia severity, it could potentially be used as a modulatory agent in the treatment of β-thalassemia.
    Matched MeSH terms: beta-Thalassemia/genetics*
  6. Wee YC, Tan KL, Kuldip K, Tai KS, George E, Tan PC, et al.
    Community Genet, 2008;11(3):129-34.
    PMID: 18376108 DOI: 10.1159/000113874
    BACKGROUND/AIMS: Individuals with double heterozygosity for alpha- and beta-thalassaemia and heterozygous beta-thalassaemia show a similar haematological picture. Co-inheritance of alpha- and beta-thalassaemia in both partners may result in pregnancies with either Hb Bart's hydrops foetalis or beta-thalassaemia major, or pregnancies with both disorders.
    METHODS: The co-inheritance of alpha-thalassaemia in 322 beta-thalassaemia carriers in Malaysia was studied.
    RESULTS: The frequency of alpha-thalassaemia in the beta-thalassaemia carriers was 12.7% (41/322), with a carrier frequency of 7.8% for the SEA deletion, 3.7% for the -alpha(3.7) deletion, 0.9% for Hb Constant Spring and 0.3% for the -alpha(4.2) deletion.
    CONCLUSION: Double heterozygosity for alpha- and beta-thalassaemia was confirmed in 5 out of the 41 couples and the risk of the fatal condition Hb Bart's hydrops foetalis was confirmed in two of these couples. Detection of the Southeast Asian (SEA) deletion in the Malaysian Malays in this study confirms that Hb Bart's hydrops foetalis can occur in this ethnic group. Results of this study have provided new information on the frequency and different types of alpha-thalassaemia (--(SEA), -alpha(3.7) and -alpha(4.2) deletions, Hb Constant Spring) in Malaysian beta-thalassaemia carriers.
    Matched MeSH terms: beta-Thalassemia/genetics*
  7. Karthipan SN, George E, Jameela S, Lim WF, Teh LK, Lee TY, et al.
    Int J Lab Hematol, 2011 Oct;33(5):540-4.
    PMID: 21884505 DOI: 10.1111/j.1751-553X.2011.01304.x
    Dried blood spots (DBS) are currently the recommended sample collection method for newborn screening programmes in America. Early diagnosis of beta-thalassaemia screening is essential as it provides an added advantage especially in sickle cell disease. Beta-thalassaemia frequency is high in many poor countries, and the cost of using commercial DNA extraction kits can be prohibitive. Our study assessed three methods that use minimal reagents and materials to extract DNA from DBS for beta-thalassaemia identification.
    Matched MeSH terms: beta-Thalassemia/genetics*
  8. Tan JA, Tay SH, Kham KY, Wong HB
    Jpn. J. Hum. Genet., 1993 Sep;38(3):315-8.
    PMID: 7903173 DOI: 10.1007/BF01874141
    The distribution of restriction fragment length polymorphism (RFLP) at the BamH1 site of the beta-globin gene was investigated in the Chinese, Indian, and Malay race in Singapore. The sample comprised of 183 normal individuals and 35 beta-thalassemia carriers in which 13 were couples with at least one beta-major child. The results from this study indicate that BamH1 polymorphism will be informative in 22% of pregnancies at risk for beta-thalassemia major in Chinese, 19% in Malays and 7% in Indians. In prenatal diagnosis using BamH1 polymorphism for one beta-major affected family, the fetus was diagnosed to be normal or beta-carrier. The validity of BamH1 polymorphism in the exclusion of beta-thalassemia major was subsequently confirmed at birth by globin chain biosynthesis.
    Matched MeSH terms: beta-Thalassemia/genetics
  9. George E
    Ann Acad Med Singap, 1994 Jan;23(1):89-93.
    PMID: 7514384
    The clinical severity of the mutations causing beta-thalassaemia in West Malaysia is presented. Thalassaemia clinical scores (Thal CS), a scoring system, has been formulated to predict clinical severity. It is the type of beta-thalassaemia mutation present that decides on the clinical phenotype. The most severe beta-thalassaemia mutation is assigned a score of 4. A score of 8 indicates a severe thalassaemia phenotype. Alpha-thalassaemia, increased synthesis of Hb F, and glucose-6-phosphate deficiency may ameliorate the clinical condition at phenotype level, and the co-inheritance of hereditary ovalocytosis aggravates it.
    Matched MeSH terms: beta-Thalassemia/genetics*
  10. George E
    Med J Malaysia, 2001 Dec;56(4):397-400.
    PMID: 12014756
    Matched MeSH terms: beta-Thalassemia/genetics*
  11. Tan JA, Chin PS, Wong YC, Tan KL, Chan LL, George E
    Pathology, 2006 Oct;38(5):437-41.
    PMID: 17008283
    In Malaysia, about 4.5% of the Malay and Chinese populations are heterozygous carriers of beta-thalassaemia. The initial identification of rare beta-globin gene mutations by genomic sequencing will allow the development of simpler and cost-effective PCR-based techniques to complement the existing amplification refractory mutation system (ARMS) and gap-PCR used for the identification of beta-thalassaemia mutations.
    Matched MeSH terms: beta-Thalassemia/genetics*
  12. Thong MK, Tan JA, Tan KL, Yap SF
    J Trop Pediatr, 2005 Dec;51(6):328-33.
    PMID: 15967770 DOI: 10.1093/tropej/fmi052
    beta-thalassaemia major, an autosomal recessive hemoglobinopathy, is one of the most common single gene disorders in multi-racial Malaysia. The control of beta-thalassaemia major requires a multi-disciplinary approach that includes population screening, genetic counselling, prenatal diagnosis and the option of termination of affected pregnancies. To achieve this objective, the molecular characterisation of the spectrum of beta-globin gene mutations in each of the affected ethnic groups is required. We studied 88 consecutive unrelated individuals and their respective families with beta-thalassaemia (74 beta-thalassaemia major, 12 HbE-beta-thalassaemia, 2 with HbE homozygotes) and four individuals with beta-thalassaemia trait that contributed a total 180 alleles for study. Using a 2-step molecular diagnostic strategy consisting of amplification refractory mutation system (ARMS) to identify the 8 most common mutations followed by other DNA-based diagnostic techniques, a total of 177 (98.3 per cent) of the 180 beta-thalassaemia alleles were characterised. One out of 91 (1 per cent) of the Chinese alleles, one out of 46 (2.2 per cent) Malay alleles and one out of two Indian alleles remained unknown. A 100 per cent success rate was achieved in studying the Kadazandusun community in this study. A strategy to identify beta-globin gene mutations in Malaysians with beta-thalassaemia is proposed based on this outcome.
    Matched MeSH terms: beta-Thalassemia/genetics*
  13. Azma RZ, Othman A, Azman N, Alauddin H, Ithnin A, Yusof N, et al.
    Malays J Pathol, 2012 Jun;34(1):57-62.
    PMID: 22870600
    Haemoglobin Constant Spring (Hb CS) mutation and single gene deletions are common underlying genetic abnormalities for alpha thalassaemias. Co-inheritance of deletional and non-deletional alpha (alpha) thalassaemias may result in various thalassaemia syndromes. Concomitant co-inheritance with beta (beta) and delta (delta) gene abnormalities would result in improved clinical phenotype. We report here a 33-year-old male patient who was admitted with dengue haemorrhagic fever, with a background history of Grave's disease, incidentally noted to have mild hypochromic microcytic red cell indices. Physical examination revealed no thalassaemic features or hepatosplenomegaly. His full blood picture showed hypochromic microcytic red cells with normal haemoglobin (Hb) level. Quantitation of Hb using high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) revealed raised Hb F, normal Hb A2 and Hb A levels. There was also small peak of Hb CS noted in CE. H inclusions was negative. Kleihauer test was positive with heterocellular distribution of Hb F among the red cells. DNA analysis for alpha globin gene mutations showed a single -alpha(-3.7) deletion and Hb CS mutation. These findings were suggestive of compound heterozygosity of Hb CS and a single -alpha(-3.7) deletion with a concomitant heterozygous deltabeta thalassaemia. Co-inheritance of Hb CS and a single -alpha(-3.7) deletion is expected to result at the very least in a clinical phenotype similar to that of two alpha genes deletion. However we demonstrate here a phenotypic modification of alpha thalassemia presumptively as a result of co-inheritance with deltabeta chain abnormality as suggested by the high Hb F level.
    Matched MeSH terms: beta-Thalassemia/genetics
  14. Tan KL, Tan JA, Wong YC, Wee YC, Thong MK, Yap SF
    Genet. Test., 2001;5(1):17-22.
    PMID: 11336396 DOI: 10.1089/109065701750168626
    Beta-thalassemia major patients have chronic anemia and are dependent on blood transfusions to sustain life. Molecular characterization and prenatal diagnosis of beta3-thalassemia is essential in Malaysia because about 4.5% of the population are heterozygous carriers for beta-thalassemia. The high percentage of compound heterozygosity (47.62%) found in beta-thalassemia major patients in the Thalassaemia Registry, University of Malaya Medical Centre (UMMC), Malaysia, also supports a need for rapid, economical, and sensitive protocols for the detection of beta-thalassemia mutations. Molecular characterization of beta-thalassemia mutations in Malaysia is currently carried out using ARMS, which detects a single beta-thalassemia mutation per PCR reaction. We developed and evaluated Combine amplification refractory mutation system (C-ARMS) techniques for efficient molecular detection of two to three beta-thalassemia mutations in a single PCR reaction. Three C-ARMS protocols were evaluated and established for molecular characterization of common beta-thalassemia mutations in the Malay and Chinese ethnic groups in Malaysia. Two C-ARMS protocols (cd 41-42/IVSII #654 and -29/cd 71-72) detected the beta-thalassemia mutations in 74.98% of the Chinese patients studied. The CARMS for cd 41-42/IVSII #654 detected beta-thalassemia mutations in 72% of the Chinese families. C-ARMS for cd 41-42/IVSI #5/cd 17 allowed detection of beta-thalassemia mutations in 36.53% of beta-thalassemia in the Malay patients. C-ARMS for cd 41-42/IVSI #5/cd 17 detected beta-thalassemia in 45.54% of the Chinese patients. We conclude that C-ARMS with the ability to detect two to three mutations in a single reaction provides more rapid and cost-effective protocols for beta-thalassemia prenatal diagnosis and molecular analysis programs in Malaysia.
    Matched MeSH terms: beta-Thalassemia/genetics*
  15. Lee TY, Muniandy L, Teh LK, Abdullah M, George E, Sathar J, et al.
    Turk J Haematol, 2016 Mar 05;33(1):15-20.
    PMID: 26377036 DOI: 10.4274/tjh.2014.0197
    The diverse clinical phenotype of hemoglobin E (HbE)/β-thalassemia has not only confounded clinicians in matters of patient management but has also led scientists to investigate the complex mechanisms involved in maintaining the delicate red cell environment where, even with apparent similarities of α- and β-globin genotypes, the phenotype tells a different story. The BTB and CNC homology 1 (BACH1) protein is known to regulate α- and β-globin gene transcriptions during the terminal differentiation of erythroid cells. With the mutations involved in HbE/β-thalassemia disorder, we studied the role of BACH1 in compensating for the globin chain imbalance, albeit for fine-tuning purposes.
    Matched MeSH terms: beta-Thalassemia/genetics*
  16. Ngim CF, Lai NM, Ibrahim H
    Prenat Diagn, 2013 Dec;33(13):1226-32.
    PMID: 24014379 DOI: 10.1002/pd.4233
    OBJECTIVE: Genetic counseling for thalassemia carriers is conducted by nongeneticist health care workers (HCWs) in many countries. The aim of the study was to assess Malaysian HCWs' genetic counseling practices with regards to discussing prenatal diagnosis (PND) and termination of pregnancy (TOP) when counseling thalassemia carriers.
    METHOD: A total of 118 Malaysian HCWs (52 doctors and 66 nurses) completed a structured questionnaire that enquired if they would discuss PND and TOP when counseling couples with thalassemia traits, and reasons for their responses were explored.
    RESULTS: All the nurses and 50 (96.1%) doctors were in favor of discussing PND. Only 29 (58%) doctors and 33 (50%) nurses were agreeable to discuss about the option of TOP. Main reasons given for declining to discuss TOP were views that "the condition was not serious enough" (54.9%), TOP is not permissible by their religion (17.6%) and abortion for this indication was illegal (13.7%).
    CONCLUSION: The results showed that HCWs in Malaysia lacked the comprehensive information and necessary skills required when counseling thalassemia carriers. When nongeneticist HCWs are tasked with such responsibilities, their practices and attitudes should be regularly evaluated so that areas of deficiencies could be identified and addressed.
    Matched MeSH terms: beta-Thalassemia/genetics
  17. Rozitah R, Nizam MZ, Nur Shafawati AR, Nor Atifah MA, Dewi M, Kannan TP, et al.
    Singapore Med J, 2008 Dec;49(12):1046-9.
    PMID: 19122960
    Beta-thalassaemia major is an autosomal recessive disorder that results in severe microcytic, hypochromic, haemolytic anaemia among affected patients. Beta-thalassaemia has emerged as one of the most common public health problems in Malaysia, particularly among Malaysian Chinese and Malays. This study aimed to observe the spectrum of mutations found in Kelantan Malay beta-thalassaemia major patients who attended the Paediatrics Daycare Unit, Hospital Universiti Sains Malaysia, Kelantan, Malaysia, the data of which was being used in establishing the prenatal diagnosis in this Human Genome Centre.
    Matched MeSH terms: beta-Thalassemia/genetics*
  18. Razak SAA, Murad NAA, Masra F, Chong DLS, Abdullah N, Jalil N, et al.
    Curr Mol Med, 2018;18(5):295-305.
    PMID: 30289070 DOI: 10.2174/1566524018666181004121604
    BACKGROUND: The phenotypic severity of β-thalassemia is highly modulated by three genetic modifiers: β-globin (HBB) mutations, co-inheritance of α-thalassemia and polymorphisms in the genes associated with fetal haemoglobin (HbF) production. This study was aimed to evaluate the effect of HbF related polymorphisms mainly in the HBB cluster, BCL11A (B-cell CLL/lymphoma 11A) and HBS1L-MYB (HBS1-like translational GTPase-MYB protooncogene, transcription factor) with regards to clinical severity.

    METHODS: A total of 149 patients were included in the study. HBA and HBB mutations were characterised using multiplex PCR, Sanger sequencing and multiplex ligationdependent probe amplification. In addition, 35 HbF polymorphisms were genotyped using mass spectrometry and PCR-restriction fragment length polymorphism (PCRRFLP). The genotype-phenotype association was analysed using SPSS version 22.

    RESULTS: Twenty-one HBB mutations were identified in the study population. Patients with HBB mutations had heterogeneous phenotypic severity due to the presence of other secondary modifiers. Co-inheritance of α-thalassemia (n = 12) alleviated disease severity of β-thalassemia. In addition, three polymorphisms (HBS1LMYB, rs4895441 [P = 0.008, odds ratio (OR) = 0.38 (0.18, 0.78)], rs9376092 [P = 0.030, OR = 0.36 (0.14, 0.90)]; and olfactory receptor [OR51B2] rs6578605 [P = 0.018, OR = 0.52 (0.31, 0.89)]) were associated with phenotypic severity. Secondary analysis of the association between single-nucleotide polymorphisms with HbF levels revealed three nominally significant SNPs: rs6934903, rs9376095 and rs9494149 in HBS1L-MYB.

    CONCLUSION: This study revealed 3 types of HbF polymorphisms that play an important role in ameliorating disease severity of β-thalassemia patients which may be useful as a predictive marker in clinical management.

    Matched MeSH terms: beta-Thalassemia/genetics*
  19. Hassan K
    PMID: 8629087
    Matched MeSH terms: beta-Thalassemia/genetics
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