Homozygous TREM-2 mutations that cause a near-complete functional loss of the TREM-2 gene (e.g. p.Q33X) or TYROBP/DAP12 have been known to be linked to an autosomal recessive disorder called polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), also known as Nasu-Hakola Disease [65–67]. Here, TREM2 is linked to Nasu-Hakola disease.