Genetic Aspects of Osteopenia/Osteoporosis in Ankylosing Spondylitis

Aim: Secondary osteoporosis with subsequent fractures are well-known symptoms in ankylosing spondylitis. As a possible genetic component of osteoporosis, an association between bone mineral density (BMD) and polymorphisms of the vitamin D receptor (VDR) gene has been reported. Method: In the present study, we investigated relationships between these polymorphisms, BMD, biochemical markers of bone metabolism and markers of disease activity in ankylosing spondylitis. Results: AS patients showed osteoporosis more frequently than healthy controls. A mapping of activity indices and BMD showed an association of lumbar and peripheral BMD as well as of the current and median C-reactive protein over the last 3 years with the used Fokl-genotypes of the VDR in male patients with AS. Female AS patients showed no significant association. Conclusion: The pathophysiological mechanisms of this association are unclear, especially with respect to the inflammatory activity. An early assessment of the risk for osteopenia/osteoporosis in AS patients using molecular biological tests could make possible timely preventive measures or therapy.