Considering these findings, and given that (i) ALS exists along a spectrum with FTD [92]; (ii) a portion of PD risk is mediated by variation near the MAPT locus [93, 94]; and (iii) ALSP can manifest clinically as FTD [18], our finding of reduced NC monocytes in familial tauopathy both strengthens and extends the purported relevance of this monocyte population in neurodegenerative disease. This evidence concerns the gene MAPT and Parkinson disease.