rhENPP1 ERT could also be a promising therapy for other diseases caused by loss-of-function mutations in ENPP1 or low plasma PPi levels, or characterized by ectopic vascular calcification, such as pseudoxanthoma elasticum, autosomal-recessive hypophosphatemic rickets and chronic kidney disease. This evidence concerns the gene ENPP1 and autosomal recessive hypophosphatemic rickets.