More generally, the increased CSF levels of soluble TREM2 in sporadic (Heslegrave et al, 2016; Piccio et al, 2016; Suárez‐Calvet et al, 2016b) and familial AD (Suárez‐Calvet et al, 2016a) argue that increased TREM2 NTF shedding is important in the common sporadic form of AD as well as in rare TREM2‐dependent forms. This evidence concerns the gene TREM2 and Alzheimer disease.