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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]

Dystrophinopathy is the commonest form of muscular dystrophy and comprises clinically recognized forms, Duchenne dystrophy and Becker dystrophy. Mutations in the dystrophin gene which consist of large gene deletions (65%), duplications (5%) and point mutations (30%) are responsible for reducing the amount of functional dystrophin protein in skeletal muscle fibres leading to fibre destruction and disease. The aims of this study are to investigate the detection rate, types and distribution of large gene deletions in Malaysian dystrophinopathy patients using the multiplex polymerase chain reaction (MPCR). MPCR of 18 "hot-spot deletion" regions along the dystrophin gene was performed on DNA from 48 muscle biopsy-confirmed cases of dystrophinopathy. A positive detection rate of 58% (28/48) was observed, where 84% (16/19) Indian, 35% (6/17) Chinese and 50% (6/12) Malay ethnic groups showed deletions in their dystrophin genes. The Malaysian Indians appear to have a higher prevalence for large gene deletions compared to the Chinese and Malays. Further analyses of 42 confirmed positive cases (present 28 plus previous 14 cases) by MPCR showed the majority of deletions were in the mid-distal region of the dystrophin gene (81% in exons 45-60). The MPCR is a specific and sensitive method for confirmation of gene deletions responsible for dystrophinopathy. [ABSTRACT FROM AUTHOR]