Apolipoprotein B 5 '-Ins/Del and 3 '-VNTR polymorphisms in Chinese, Malay and Indian Singaporeans

The allele frequencies for the apolipoprotein B (apo B) 5'-lns/Del and 3'-V NTR polymorphisms varied significantly (p < 0.01) among Singaporeans of Chi nese, Malay and Indian descent. We calculated the unbiased expected heteroz ygosities for the 5'-lns/Del polymorphism as 0.3357, 0.1984 and 0.2418, and for the 3'-VNTR as 0.5980, 0.5260 and 0.6749, respectively, in the Chinese , Malays and Indians. Compared to heterozygosities reported for other popul ations, the Singaporeans differed from most Caucasians in having significan tly lower values but were closely related to other non-Caucasians. Thirteen alleles, with a bimodal distribution, were observed at the 3'-VNTR polymor phic locus; the alleles occurring most frequently among the Chinese and Mal ays were of 35 or 53 repeats, and among the Indians, of 37 or 47 repeats. T he Del allele was associated with elevated serum cholesterol (p = 0.023), L DL-cholesterol (LDL-C) (p = 0.001) in the Chinese, and apo B (p = 0.007) in the Indians. Likewise, the larger 3'-VNTR alleles (> 41 repeats) were asso ciated with raised cholesterol (p = 0.018), LDL-C (p = 0.025), and triglyce ride (p = 0.001) in the Chinese. The two polymorphisms were not in signific ant linkage disequilibrium (D = -0.0029, p = 0.494) in the three ethnic gro ups.