A Powerful Method for Pleiotropic Analysis Under Composite Null Hypothesis Identifies Novel Shared Loci Between Type 2 Diabetes and Prostate Cancer

In December 2020, researchers Debashree Ray and Nilanjan Chatterjee introduced a new statistical method, PLACO, for identifying shared genetic variants between two traits, specifically Type 2 Diabetes and Prostate Cancer. The method was designed to test the null hypothesis that a variant is associated with none or only one of the traits. Simulation studies showed that PLACO could maintain type I error and achieve major power gain over alternative methods typically used for testing pleiotropy. The researchers applied PLACO to publicly available summary data from two large case-control genome-wide association studies (GWAS) of Type 2 Diabetes and Prostate Cancer. The analysis identified several novel shared genetic regions that were not detected by individual trait analysis. Many of the loci implicated by PLACO increased risk for one disease while decreasing risk for the other.