However, other studies show that TREM2 loss of function is associated with a drastically elevated AD risk (Jin et al, 2014; Cheng‐Hathaway et al, 2018) and with facilitated Aβ‐associated tau seeding in AD mice expressing both Aβ and tau pathology (Leyns et al, 2019; Gratuze et al, 2021). Here, TREM2 is linked to Alzheimer disease.