What are the genetic changes related to polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy ?
Mutations in the TREM2 gene or the TYROBP gene (also called DAP12) can cause PLOSL. The proteins produced from these two genes work together to activate certain kinds of cells. These proteins appear to be particularly important in osteoclasts, which are specialized cells that break down and remove (resorb) bone tissue that is no longer needed. These cells are involved in bone remodeling, which is a normal process that replaces old bone tissue with new bone. The TREM2 and TYROBP proteins are also critical for the normal function of microglia, which are a type of immune cell in the brain and spinal cord (central nervous system). Although these proteins play essential roles in osteoclasts and microglia, their exact function in these cells is unclear.  Mutations in the TREM2 or TYROBP gene disrupt normal bone growth and lead to progressive brain abnormalities in people with PLOSL. Researchers believe that the bone changes seen with this disorder are related to malfunctioning osteoclasts, which are less able to resorb bone tissue during bone remodeling. In the central nervous system, TREM2 or TYROBP mutations cause widespread abnormalities of microglia. Researchers are working to determine how these abnormalities lead to the progressive neurological problems associated with PLOSL.