An exome-wide sequencing study of lipid response to high-fat meal and fenofibrate in Caucasians from the GOLDN cohort

Abstract

Our understanding of genetic influences on the response of lipids to specific interventions is limited. In this study, we sought to elucidate effects of rare genetic variants on lipid response to a high-fat meal challenge and fenofibrate (FFB) therapy in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) cohort using an exome-wide sequencing-based association study. Our results showed that the rare coding variants in ITGA7, SIPA1L2, and CEP72 are significantly associated with fasting LDL cholesterol response to FFB (P = 1.24E-07), triglyceride postprandial area under the increase (AUI) (P = 2.31E-06), and triglyceride postprandial AUI response to FFB (P = 1.88E-06), respectively. We sought to replicate the association for SIPA1L2 in the Heredity and Phenotype Intervention (HAPI) Heart Study, which included a high-fat meal challenge but not FFB treatment. The associated rare variants in GOLDN were not observed in the HAPI Heart study, and thus the gene-based result was not replicated. For functional validation, we found that gene transcript level of SIPA1L2 is associated with triglyceride postprandial AUI (P < 0.05) in GOLDN. Our study suggests unique genetic mechanisms contributing to the lipid response to the high-fat meal challenge and FFB therapy.

Keywords: cholesterol; epidemiology; genetics; high-density lipoprotein; low-density lipoprotein; postprandial lipemia; rare variant; triglyceride; whole-exome sequencing.

Fig. 1.

Fraction of SNPs with different MAF range within different categories. The categories include synonymous, nonsynonymous, and loss of function (i.e., splicing, stopgain, and stoploss). The y axis indicates the fraction of SNPs with a different MAF range.

Fig. 2.

Distribution of residuals for regression of phenotypes on their covariates. The diamonds indicate corresponding residual values of rare variant carriers. The x axis is the Z score for residuals. The y axis is the sample counts.