Search

Background: Thalassaemia is a common public health problem in Malaysia and about 4.5 to 6% of the Malays and Chinese are carriers of this genetic disorder. The major forms of thalassaemia result in death in utero of affected foetuses (α-thalassaemia) or life-long blood transfusions for survival in β-thalassaemia. This study, the first nationwide population based survey of thalassaemia in Malaysia, aimed to determine differences in public awareness, perceptions and attitudes toward thalassaemia in the multi-racial population in Malaysia., Methods: A cross-sectional computer-assisted telephone interview survey of a representative sample of multi-racial Malaysians aged 18 years and above was conducted between July and December 2009., Results: Of a total of 3723 responding households, 2846 (76.4%) have heard of thalassaemia. Mean knowledge score was 11.85 (SD ± 4.03), out of a maximum of 21, with higher scores indicating better knowledge. Statistically significant differences (P < 0.05) in total knowledge score by age groups, education attainment, employment status, and average household income were observed. Although the majority expressed very positive attitudes toward screening for thalassaemia, only 13.6% of married participants interviewed have been screened for thalassaemia. The majority (63.4%) were unsupportive of selective termination of foetuses diagnosed with thalassaemia major., Conclusion: Study shows that carrier and premarital screening programs for thalassaemia may be more effective and culturally acceptable in the reduction of pregnancies with thalassaemia major. The findings provide insights into culturally congruent educational interventions to reach out diverse socio-demographic and ethnic communities to increase knowledge and cultivate positive attitudes toward prevention of thalassaemia.

Beta-thalassemia is one of the most prevalent inherited diseases and a public health problem in Malaysia. Malaysia is geographically divided into West and East Malaysia. In Sabah, a state in East Malaysia, there are over 1000 estimated cases of β-thalassemia major patients. Accurate population frequency data of the molecular basis of β-thalassemia major are needed for planning its control in the high-risk population of Sabah. Characterization of β-globin gene defects was done in 252 transfusion dependent β-thalassemia patients incorporating few PCR techniques. The study demonstrates that β-thalassemia mutations inherited are ethnically dependent. It is important to note that 86.9% of transfusion-dependent β-thalassemia major patients in Sabah were of the indigenous population and homozygous for a single mutation. The Filipino β0-deletion was a unique mutation found in the indigenous population of Sabah. Mutations common in West Malaysia were found in 11 (4.3%) patients. Four rare mutations (Hb Monroe, CD 8/9, CD 123/124/125 and IVS I-2) were also found. This study is informative on the population genetics of β-thalassemia major in Sabah. [ABSTRACT FROM AUTHOR]

Introduction: Interactions of different hemoglobin variants with thalassemia alleles can result in various clinical phenotypes. HbE-beta-thalassemia generally manifests with severe anemia where individuals exhibit beta-thalassemia major with regular blood transfusions or beta-thalassemia intermedia with periodic blood transfusions. This study presents a unique Malay family with three beta-globin gene defects-HbE, Hb South Florida, and IVS1-1 (G-->A).Materials and Methods: HbE activates a cryptic splice site that produces non-functional mRNAs. Hb South Florida is a rare beta-hemoglobin variant, and its interactions with other beta-thalassemia alleles have not been reported. IVS1-1 is a Mediterranean mutation that affects mRNA processing giving rise to beta(o)-thalassemia.Results and Discussion: Fifteen mutations along the beta-globin gene complex were analyzed using the amplification refractory mutation system. Hb South Florida was identified by direct sequencing using genomic DNA.Conclusion: The affected child with HbE/IVS1-1 produced a beta-thalassemia major phenotype. Compound heterozygosity for Hb South Florida/IVS1-1 produced a beta-thalassemia carrier phenotype in the mother. [ABSTRACT FROM AUTHOR]

Co-inheritance of α-thalassemia with homozygosity or compound heterozygosity for Β-thalassemia may ameliorate Β-thalassemia major. A wide range of clinical phenotypes is produced depending on the number of α-thalassemia alleles (-α/αα--/αα, --/-α). The co-inheritance of Β-thalassemia with α-thalassemia with a single gene deletion (-α/αα) is usually associated with thalassemia major. In contrast, the co-inheritance of Β-thalassemia with two α-genes deleted in cis or trans (--/αα or -α/-α) generally produces Β-thalassemia intermedia. In Southeast Asia, the most common defect responsible for α-thalassemia is the Southeast Asian (SEA) deletion of 20.5 kilobases. The presence of the SEA deletion with Hb Constant Spring (HbCS) produces HbH-CS disease. Co-inheritance of HbH-CS with com-pound heterozygosity for Β-thalassemia is very rare. This study presents a Malay patient with HbH-CS disorder and Β°/Β+-thalassemia. The SEA deletion was confirmed in the patient using a duplex-PCR. A Combine-Amplification Refractory Mutation System (C-ARMS) technique to simultaneously detect HbCS and Hb Quong Sze confirmed HbCS in the patient. Compound heterozygosity for CD41/42 and Poly A was confirmed using the ARMS. This is a unique case as the SEA α-gene deletion in cis (--SEA/αα) is generally not present in the Malays, who more commonly posses the two a-gene deletion in trans (-α/-α). In addition, the Β-globin gene mutation at CD41/42 is a common mutation in the Chinese and not in the Malays. The presence of both the SEA deletion and CD41/42 in the mother of the patient suggests the possible introduction of these two defects into the fam-ily by marriage with a Chinese. [ABSTRACT FROM AUTHOR]

Aim: Interactions between different determinants of α-thalassemia raises considerable problems, particularly during pregnancies where antenatal diagnosis is necessary. This study aims to determine the different types of deletional α-thalassemia and Hemoglobin Constant Spring (HbCS), and their frequency in Malays, Chinese and Indians in Malaysia. Methods: DNA from 650 pregnant women from the Antenatal Clinic of the University of Malaya Medical Center in Kuala Lumpur, Malaysia who showed mean cell volume ≤89 fL and/or mean cell hemoglobin ≤28 pg were analyzed for the double α-globin gene South-East Asian deletion (--SEA), the -α3.7 and -α4.2 single α-globin gene deletions and HbCS. Results: One hundred and three (15.8%) of the pregnant women were confirmed as α-thalassemia carriers: 25 (3.8%) were α-thalassemia-1 carriers with the --SEA/αα genotype, 64 (9.8%) were heterozygous for the -α3.7 rightward deletion (-α3.7/αα), four (0.6%) were heterozygous for the -α4.2 leftward deletion (-α4.2/αα), nine (1.4%) were heterozygous for HbCS (αCSα/αα) and one (0.2%) was compound heterozygous with the -α3.7/αCSα genotype. The double α-globin gene --SEA deletion was significantly higher in the Chinese (15%) compared to the Malays (2.5%) and not detected in the Indians studied. The -α3.7 deletion was distributed equally in the three races. HbCS and -α4.2 was observed only in the Malays. Conclusion: The data obtained gives a better understanding of the interactions of the different α-thalassemia determinants in the different ethnic groups, thus enabling more rapid and specific confirmation of α-thalassemia in affected pregnancies where antenatal diagnosis is necessary. [ABSTRACT FROM AUTHOR]

Molecular characterization of the compound heterozygous condition--[supG]γ([supA]γδΒ)[supo]/Β-thalassemia--in four families showing mild Β-thalassemia intermedia was carried out using DNA amplification techniques. Using the Amplification Refractory Mutation System (ARMS) to confirm the Β-mutations and DNA amplification to detect the 100-kb Chinese-specific [supG]γ([supA]γδΒ)[supo]-deletion, two families were confirmed to possess [supG]γ([supA]γδΒ)[supo]/&Beta-thalassemia with the IVSII No. 654 Β[sup+]-allele. In the third family, the [supG]γ([supA]γδΒ)[supo]-deletion was confirmed in the father and the mother was a Β-thalassemia carrier with the cd 41-42 Β[supo]-allele. Their affected child with [supG]γ([supA]γδΒ)[supo]/Β-thalassemia was found to be transfusion dependent. The same [supG]γ([supA]γδΒ)[supo]-deletion and Β-thalassemia (cd 41-42) was also confirmed in a fourth family. In addition, the mother was also diagnosed with Hb H disease (genotype-α[sup3.7]/[sup-SEA]). Both the children were found to possess [supG]γ([supA]γδΒ)[supo]/Β-thalassemia but they were not transfusion dependent and this could be due to co-inheritance of α-thalassemia-2 (genotype-α[sup3.7]/αα) in the children together with their compound heterozygous condition. [ABSTRACT FROM AUTHOR]