MAPT and Cognitive impairment: Regarding clinical phenotypes, the C9orf72 patients included 10 bvFTD, 1 nfvPPA, 1 corticobasal syndrome (CBS), 4 FTD‐ALS, 2 pure ALS (1 bulbar and 1 spinal onset), and 1 ALS with cognitive impairment (not meeting criteria for FTD diagnosis), MAPT carriers included 1 bvFTD and 1 svFTD, 6 GRN mutations carriers were diagnosed with bvFTD, 5 with nfvPPA, and 1 with Parkinson's disease (PD) phenotype associated with prodromal FTD (Table 1, Tables S1 and S2).