ENPP1 and Pseudoxanthoma elasticum: Pathogenic variants in ENPP1 are associated with several genetic disorders, including three autosomal recessive conditions: generalized arterial calcification of infancy (GACI [MIM 208000]), autosomal recessive hypophosphatemic rickets (ARHR2 [MIM 613312]), and pseudoxanthoma elasticum (PXE [MIM 264800]), along with autosomal dominant Cole disease [MIM 615522] and insulin resistance and type 2 diabetes.