Perhaps not too surprising, TREM2 deficiencies have been associated with pathological deficits in phagocytosis, amyloidogenesis and a compromised innate immune system in the inflammatory, neuro-degenerative illnesses polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) and more recently with late onset Alzheimer's disease (AD; Forabosco et al., 2013; Golde et al., 2013; Guerreiro et al., 2013; Jonsson et al., 2013; Neumann and Daly, 2013; Zhao et al., 2013). This evidence concerns the gene TREM2 and Alzheimer disease.