For example, a NGS-based study on CAD was carried out in 2015, they scanned each gene of ∼5000 cases with early-onset CAD to controls without CAD in order to find genes of significant associations with CAD, the result showed that 2% of studied early-onset CAD patients harbored at least a rare variant on LDLR, which is a long recognized gene relating to hypercholesterolemia and CAD [8]. The gene discussed is LDLR; the disease is familial hypercholesterolemia.