In conclusion, the homozygous loss-of-function mutation in DMP1 resulted in hypophosphatemia and severe progressive skeletal dysplasia characterized clinically by short stature, joint pain, contractures, and immobilization of the spine and radiographically by short and deformed long bones, significant cranial hyperostosis, enthesopathies, and calcifications of the paraspinal ligaments. The gene discussed is DMP1; the disease is hypophosphatemia.