PD-significant SNPs results in considerable increase in statistical power for AD gene discovery. We also calculated the sample size needed to detect rs393152 ((C−1 Θ−1(5 × 10−8)2/ Θ−1(0.00625)2), where Θ−1 is the inverse standard normal cumulative distribution function) and found that in comparison to our discovery cohort, 4.5 times as many subjects would be needed to detect rs393152 using a standard GWAS approach at the same alpha /Type I error.
