From OMIM
Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) is characterized by presenile dementia along with large-scale destruction of cancellous bones. Initial symptoms, starting in the twenties, are pain and swelling resulting from cysts in the wrists and ankles. Extremity bone fractures could occur with minor trauma. At around 30 years of age, patients gradually develop neuropsychiatric symptoms, including epileptic seizures, agnosia, apraxia, speech disorder, memory disturbance, euphoria, and loss of social inhibitions. The disorder usually leads to death in the fifth decade of life (summary by Kondo et al., 2002). Genetic Heterogeneity of Polycystic Lipomembranous Osteodysplasia with Sclerosing Leukoencephalopathy Also see PLOSL2 (618193), caused by mutation in the TREM2 gene (605086) on chromosome 6p21.  http://www.omim.org/entry/221770