Gender and ethnic differences in a case-control study of dyslipidemia: using the apolipoprotein A-V gene as an exemplar in cardiovascular genetics.

Common, complex genetic disorders such as coronary heart disease (CHD) frequently show large population differences, contributing to health disparities. It is also well known that CHD risk factor profiles and the frequency of coronary events differ by gender. Study of premature CHD has revealed that apolipoproteins are important discriminating factors for distinguishing individuals with CHD. Recent findings indicated that apolipoprotein A-V (APOA-V) gene promoter polymorphisms are an important determinant of plasma triglycerides (TG) and lipoprotein cholesterol, and a risk factor for CHD. Variations in APOA-V may have varying impacts in different ethnic groups. The purpose of this interdisciplinary genetic research project was to determine (1) the association of the APOA-V polymorphisms with lipoprotein profiles, and (2) the gender and ethnic differences in the T-1131C promoter polymorphism of the APOA-V gene in individuals with dyslipidemia versus controls. Results indicate that the minor -1131C allele (CC homozygotes + CT heterozygotes) was associated with elevated plasma TG (p = 0.007), very low density lipoprotein (VLDL)-TG (p = 0.019), LDL-TG (p = 0.004), high-density-lipoprotein (HDL)-TG (p < 0.001), and VLDL-cholesterol (p = 0.008). We found a striking elevation in the frequency of the minor C allele in Asians (p < 0.001) compared to Europeans. We also found a significant difference in genotype frequency between men and women in Asians (p = 0.031) and Europeans (p < 0.01). Remarkably, Asian women with the C allele have a 36% increase in TG compared to Asian women homozygous for the T allele. In summary, we found significant ethnic-specific and gender-based differences in the frequency of the minor allele of the -1131 APOA-V gene promoter polymorphism. Identification of genetic variations among ethnic groups and between genders may have significant potential for a better understanding of the development of cardiovascular disease.