ABCC6 and Pseudoxanthoma elasticum: Identical pathogenic variants in ABCC6 or ENPP1 have been shown to cause either PXE or GACI in different patients.(7) For example, an identical homozygous pathogenic variant in ENPP1 led to one family member presenting with ARHR2 without arterial calcification and the second family member presenting with arterial calcification and hypophosphatemia.(17) This suggests that genetic modifiers play a role in the presenting phenotype.