Thus, there has been a conundrum as to whether this association of rs17632542 SNP with PCa risk is due to a true biological role of the SNP in PCa pathogenesis or simply reflects the impact of this SNP on PSA measurement, as cases and disease-free controls recruited in most of the GWAS studies have a selection bias based on PSA testing being used to detect the disease. The gene discussed is KLK3; the disease is posterior cortical atrophy.