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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]

p53gene mutation is not a frequent event in the tumorigenesis of lymphomas and the expression of p53 protein is independent ofp53gene mutations. The present study aimed to investigate mutations in thep53gene in a series of extranodal B-cell lymphomas, and its association with p53 protein expression. A total of 52 cases were graded histologically into Grade 1, Grade 2 and Grade 3 tumors and p53 protein expression was detected using immunohistochemistry. Mutations in thep53gene were analyzed using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and mobility shifts were confirmed by direct sequencing. The tumors comprised 26 (50%) Grade 1, 9 (17%) Grade 2 and 15 (29%) Grade 3. A high proportion of Grade 2 (25%) tumors expressed p53 protein (P = 0.051) and carriedp53gene mutation (33%) (P = 0.218). However, p53 protein expression was not associated withp53gene mutations (P = 0.057). Transversion mutations (88%) were more frequently detected than transition mutations (12%). The present study revealed thatp53gene mutations and p53 protein expression occurred in higher frequencies in Grade 2 tumors, which may be of pathogenetic importance. The high frequency of transversion mutations may reflect the influence of an etiological agent in the tumorigenesis of mucosa-associated lymphoid tissue (MALT lymphoma). [ABSTRACT FROM AUTHOR]