Increased frequency of apolipoprotein B signal peptide sp24/24 in patients with coronary artery disease. General allele survey in the population of Taiwan and comparison with Caucasians.

Apolipoprotein B (apoB) signal peptide (sp) polymorphism was characterized by polymerase chain reaction in blood samples of 58 coronary artery disease (CAD) patients and 319 control individuals of Chinese Han ethnic origin in Taiwan. In the CAD group, 77% of the observed alleles were sp27 (sp with 27 amino acids), and the remaining 23% sp24 (sp with 24 amino acids). The frequency distributions of the apoB sp allele in the control group were 0.81 for sp27 and 0.19 for sp24. The genotype distributions were 0.64 sp27/27, 0.26 sp27/24 and 0.10 sp24/24 in the CAD group; 0.64 sp27/27, 0.33 sp27/24 and 0.03 sp24/24 in the control group. The frequency of sp24/24 was significantly higher (p = 0.012) in the CAD group than in the control group. Several studies have shown that the frequency of sp24/24 is higher in hyperlipidemic than in normolipidemic groups. This marker is probably in linkage disequilibrium with some other atherogenic genes. Our study shows that the differences in both apoB signal peptide alleles and sp27/27 and sp27/24 genotype distributions are statistically significant between the Taiwanese and Caucasians.