Recent advances in cataloging human genetic polymorphisms, in addition to the decreasing cost of high throughput SNP genotyping and the development of statistical methodology to analyze large sample sets in a rigorous manner have made genome-wide association studies (GWAS) a feasible method for genetic studies of complex disorders [84]. Based on the hypothesis that a proportion of the genetic susceptibility for common diseases may be caused by common genetic variants that arose early in human history and thus are shared across members of a population derived from a common set of ancestors (the common-disease, common variant or CDCV hypothesis), this approach has been remarkably successful, with over 150 common variants identified within the past 2 years [84, 98].
