To help prioritize association signals from GWAS and to better understand the biological themes underlying complex diseases, gene set analysis has become increasingly popular. Instead of conducting analysis for single SNPs or single genes, gene set analysis tests disease association with genetic variants in a group of functionally related genes, such as those belonging to the same biological pathway. One possible cause of complex diseases is the changes in activities of biological pathways: where there are a number of mutations in different genes, each contributes a modest amount to disease predisposition and work together to cause disruptions in normal biological processes.
