Similar serum levels of PIVKA-II (protein induced by vitamin K absence or antagonist-II, uncarboxylated prothrombin) were measured in PXE patients compared to controls, confirming that the vitamin K-dependent coagulation factors are not affected in PXE, contrary to PXE-like syndrome (see below) [55]. The gene discussed is F2; the disease is autosomal recessive inherited pseudoxanthoma elasticum.