Additionally, recent evidence indicates that both heterozygous and compound heterozygous pathogenic variants in ENPP1, which cause Autosomal Recessive Hypophosphatemic Rickets Type 2 (ARHR2) as well as Generalized Arterial Calcification of Infancy (GACI), may also increase the risk for DISH and OPLL. This evidence concerns the gene ENPP1 and ossification of the posterior longitudinal ligament of the spine.