XPR1 and bilateral striopallidodentate calcinosis: Mutations in 6 genes, including solute carrier 20 member 2 (SLC20A2), xenotropic and polytropic retrovirus receptor 1 (XPR1), myogenesis regulating glycosidase (MYORG), junctional adhesion molecule B (JAM2), platelet-derived growth factor B (PDGFB), and platelet-derived growth factor receptor β (PDGFRB), have been found so far to cause PFBC (21).