Fetuin-A, a phosphorylated liver glycoprotein and potent systemic calcification inhibitor, is known to be significantly reduced in the serum of Abcc6−/− mice and human PXE patients, while restoring normal serum fetuin-A levels rescued the ectopic calcification phenotype in Abcc6−/− mice [35,36,37]. This evidence concerns the gene AHSG and Pseudoxanthoma elasticum.