Figure 1. The figure shows a cartoon of the 5-leukotriene synthetic pathway. Variants in the genes encoding FLAP and LTA4H conferring risk of heart attack are both associated with increased production of LTB4 (Helgadottir et al., 2004, 2006). Hence, it appears that both variants confer increase in the risk of heart attack by upregulating the leukotriene pathway. One way to contain the risk may be by turning down the pathway pharmacologically.

Figure 2. The figure shows a hypothetical graph where each point on the graph represents a sequence variant influencing the expression of a disease gene. The farther away from the centre of the x-axis, the greater the effect of the variant and the less is its frequency. Our hypothesis is that the genetics of common/complex traits is often the same as the genetics of gene expression and that individuals at one end of the spectrum of expression are at a greater than average risk and those at the other end are at a lesser than average risk. Where on the spectrum of expression the individual falls decides where on the spectrum of physiologic function he falls. This hypothesis is supported by data coming from many sources including those showing that there may be several sequence variants over the same gene each conferring distinct risk of or protection against a disease.