The classic form of GACI is caused by mutations in the ENPP1 gene, which encodes ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), an enzyme that hydrolyses ATP to AMP and inorganic pyrophosphate (PPi) [2, 3]. Here, ENPP1 is linked to arterial calcification, generalized, of infancy, 1.