To investigate the possibility that ENPP1 deficiency may be an unrecognized contributing factor to spinal enthesopathies in DISH and OPLL, a clinical study examining the skeletal, biochemical, and genetic findings in patients with DISH was performed to investigate the relationship between FGF23, plasma PPi, spinal disease, and genetic background (89). The gene discussed is FGF23; the disease is enthesopathy.