MAPT and amyotrophic lateral sclerosis: This was to be expected in c9orf72 pathogenic variant carriers but is rather unexpected in GRN and MAPT pathogenic variant carriers, as the occurrence of ALS-like signs has only rarely been described in these conditions.4,24 Of interest, this was only in part due to the nonspecific variables with high cross loadings on the PSP-MP and PD-MP contained in this phenotype cluster, as the frequency of the remaining signs of the third component was still 16.1% in GRN and 15.8% in MAPT pathogenic variant carriers, with the most frequent sign being hyperreflexia.