Its role in the pathogenesis of PFBC may be due to an altered quality control process on the folding or maturation of one or more of the protein products of genes linked to PFBC including SLC20A2, PDGFB, PDGFRB, and XPR1 [15–18], which are, in fact, all glycoproteins. The gene discussed is XPR1; the disease is bilateral striopallidodentate calcinosis.