To investigate whether, and how, the R47H variant of TREM2 reported in AD (Soragna et al., 2003; Jiang et al., 2013) affected the trafficking of TREM2, the R47H mutation was introduced into TREM2 and the variant protein was expressed in HeLa cells (Figure 1B and Supplementary Figure 1). Here, TREM2 is linked to Alzheimer disease.