APP and dementia: SKAT-O analysis revealed that none of the dementia-related genes achieved statistical significance in the WUSTL series [APP (p = 0.89), GRN (p = 0.63), PSEN1 (p = 0.13), and PSEN2 (p = 0.5)] or PPMI [APP (p = 0.15), GRN (p = 0.6), PSEN1 (p = 0.9) and PSEN2 (p = 0.09)] compared with in-house controls (Supplementary Tables 2, 4).