**4. Genetic variants in lipid metabolism and TG levels**

Plasma triglycerides (TG) integrate multiple TG-rich lipoprotein particles, predominantly, intestinally synthesized chylomicrons in the postprandial state and hepatically synthesized VLDL in the fasted state. Therefore, not surprisingly, there is considerable overlap between genetic variants associated with HDL-C and LDL-C levels as well as TG levels. For example, the Global Lipids Genetics Consortium (GLGC) found that 15 of the 32 loci associated with TG levels were also jointly associated with HDL-C levels, explaining 9.6% of the total variation in plasma TG, which corresponded to 25–30% of the total genetic contribution to TG variability (Teslovich et al., 2010). However, the joint associations reported do not appear additionally adjusted for the other lipid phenotype. Furthermore, certain loci appear to be more strongly associated with one lipid phenotype over the other while others have similar effect sizes; and, genetic heterogeneity between loci clearly exists between major ethnic groups.
