While seemingly unrelated to PSP, a curious number of neurodegeneration-related genes are also involved in bone diseases (e.g. TREM2, which has been linked to AD and Nasu-Hakola disease [37, 38], and VCP, linked to amyotrophic lateral sclerosis and Paget’s disease of bone [39, 40]). Here, TREM2 is linked to Alzheimer disease.