TREM2 and Alzheimer disease: In this study we identify functional deficits of the R47H TREM2 AD risk variant using human iPSC-derived microglia (iPS-Mg) from patients harbouring a single copy of the TREM2 R47H polymorphism (R47Hhet), in response to PS expressed on dead cells (PS+ cells) and DOPS liposomes.