[Genetic aspects of osteopenia/osteoporosis in ankylosing spondylitis]

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.

In the present study, we investigated relationships between these polymorphisms, BMD, biochemical markers of bone metabolism and markers of disease activity in ankylosing spondylitis.

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 FokI-genotypes of the VDR in male patients with AS. Female AS patients showed no significant association.

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.