TREM2 and Alzheimer disease: The fact that TREM2 heterozygous variants in particular impair the phagocytosis of apoptotic cells is of relevance to AD, in which heterozygous TREM2 variants (mainly the R47H variant) were found to be associated with AD (Guerreiro et al., 2013a, Jonsson et al., 2013), although further studies with cells from patients harboring this specific mutation are required for confirmation.