A potential role for vitamin K and its related compounds in the pathogenesis of ectopic mineralization disorders was suggested by two distinct findings: I) GGCX mutations cause a rare calcification phenotype similar to that of PXE, but accompanied by deficiencies in vitamin K-dependent clotting factors; and II) PXE patients have significantly lower serum levels of vitamin K compared to the reference population (Figure 2) [10,13]. Here, GGCX is linked to Pseudoxanthoma elasticum.