Although a number of genes may be involved (Li Q. et al., 2009; Omarjee et al., 2019; Boraldi et al., 2020a), PXE is mostly associated with ATP-binding cassette sub-family C member 6 (ABCC6) mutations (Le Saux et al., 2000), even though ABCC6 is not expressed at the protein level in cells of tissues undergoing calcification (Matsuzaki et al., 2005). This evidence concerns the gene ABCC6 and pseudoxanthoma elasticum (inherited or acquired).