In 2019, IGAP did the largest GWAS of clinically diagnosed Alzheimer’s disease to date.9 This analysis increased the IGAP Stage 1 discovery sample to 21 982 cases and 41 944 controls (n=63 926, approximately 9% of cases and controls with confirmed pathology). The meta-analysis with replication samples from stages 2 and 3 produced a final sample size of 35 274 cases and 59 163 controls (n=94 437). As a result, 24 susceptibility loci were discovered.
