No abstract

A 31-bp variable number of tandem repeats (VNTR) polymorphism of the cystathionine β-synthase (CBS) gene was earlier reported in Caucasians of predominantly European descent and Indo-Caucasoid populations. We report here for the first time, the detection of allele 20, which was absent in Caucasian and Indo-Caucasoid populations, as a common allele present in Singaporean Chinese (6.25%), Indians (11.7%), and Malays (11.5%). Hence, allele 20 might be a specific allele for Asian populations. A relatively common allele 19 found in the Caucasian and Indo-Caucasoid populations (10.4%-10.6%) was absent in the Asian samples of this study. Therefore, allele 19 might be a specific allele for the Caucasian populations. A novel and rare allele 13, which was not reported before in the Caucasian and Indo-Caucasoid populations, was found in 0.5% of Singaporean Chinese as genotype 13/17 heterozygotes. The presence of alleles 13 and 20 were verified by DNA sequencing. There were five new genotypes (13/17, 16/20, 17/20, 18/20 and 20/20) not reported before in the Caucasian and Indo-Caucasoid populations, detected in this study. Nine genotypes (15/18, 16/18, 16/21, 17/19, 18/19, 18/21, 19/19, 19/21 and 21/21) which were present in the Caucasian and/or Indo-Caucasoid populations were absent in this study. Our results showed that CBS 31-bp VNTR polymorphism has a distinct genetic difference in allele and genotype frequencies between the European Caucasians, Indo-Caucasoid and Asian populations.