[Rathbun syndrome (hypophosphatasia). Clinical aspects: dwarfism and Bechterew symptoms]

We report on a 43-year-old patient with short stature (hyposomia), allegedly the result of vitamin-D-resistant rickets, previously treated for ankylosing spondylitis. In addition, a uricostatic drug therapy was also necessary because of hyperuricemia with gout attacks. Further examinations revealed the accurate diagnosis: Rathbun's disease. Hypophosphatasia is a hereditary disorder characterized by a deficiency of liver/bone/kidney alkaline phosphatase activity in serum and tissues with defective bone mineralization, bone deformities, short stature, early loss of teeth, and craniosynostosis. In our patient radiographic features were spinal hyperostosis, but with syndesmophytes, chondrocalcinosis of peripheral joints and intervertebral discs, calcific periarthritis and premature closure of skull sutures. Curved ribs and short stature were suggestive of rickets. The aim of this case report is to demonstrate the close relations between hypophosphatasia and spondylitis ankylosans in respect to radiology and clinical symptoms.