Natural History Study of ENPP1 Deficiency and and the Early-onset Form of ABCC6 Deficiency

The purpose of this prospective study is to characterize the natural history of ENPP1 Deficiency (including Generalized Arterial Calcification of Infancy Type 1 [GACI] and Autosomal Recessive Hypophosphatemic Rickets Type 2 [ARHR2]) and the early-onset form of ABCC6 Deficiency (Generalized Arterial Calcification of Infancy Type 2 [GACI-2]) longitudinally.