ENPP1 Deficiency—caused by biallelic variants in ENPP1—leads to widespread arterial calcification in early life (Generalized Arterial Calcification of Infancy, GACI) or hypophosphatemic rickets in later life (Autosomal Recessive Hypophosphatemic Rickets type 2, ARHR2). The gene discussed is ENPP1; the disease is hypophosphatemic rickets, autosomal recessive, 2.