Loss-of-function mutations of TREM2 or DAP12 cause Nasu-Hakola disease (NHD), also named polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), a very rare inherited severe neurodegenerative disease that is associated with bone fractures, frontal lobe syndrome, progressive presenile dementia and early death in the fourth or fifth decade of life [23–26]. The gene discussed is TREM2; the disease is Nasu-Hakola disease.