According to the mechanisms involved in pseudoxanthoma elasticum, due to mutations in ABCC6 accounting for low [PPi]pl (Le Saux et al., 2000) and vascular calcification (Leftheriotis et al., 2013), it could be that the production of PPi related to ABCC6 was decreased in our patients. This evidence concerns the gene ABCC6 and Pseudoxanthoma elasticum.