The most frequent phenotype reported in the 125 patients diagnosed with GACI was arterial or aortic calcification present in 87.2% of patients (85.9% of GACI patients without ARHR2 (85/99) and 92.3% of GACI patients with ARHR2 (24/26)) (Figure 5). Here, ENPP1 is linked to arterial calcification, generalized, of infancy, 1.