It is therefore noteworthy the occurrence of a clinical and genetic overlapping between PXE and GACI as clearly highlighted by a recent study on two brothers born from to unrelated parents, showing that the elder developed a PXE condition bearing ABCC6 mutations, whereas the younger died at 15 months of age of a condition clinically reminiscent of GACI, although it appeared independent of ENPP1 mutations (Le Boulanger et al., 2010). Here, ENPP1 is linked to Pseudoxanthoma elasticum.