[Genetics of osteoporosis]

Osteoporosis is a disease affecting mainly women but also an increasing number of men. The destruction of the bone microarchitecture and the reduction of bone mass lead to increased fragility and pathologic bone fractures. Family studies and twin studies have shown that peak bone mass, mechanical strength, and physiological bone turnover are subject to genetic control. Vitamin D receptor polymorphisms were one of the first genetic factors suggested to influence bone phenotype, although their impact on bone metabolism was initially overestimated. Meanwhile, polymorphisms in numerous other genes such as collagen I alpha 1, estrogen receptor, transforming growth factor beta (TGF-beta), interleukin-1, interleukin-6, calcitonin, parathyroid hormone, and apolipoprotein E have been found to be associated with bone mineral density. In the interpretation of genetic findings, genetic differences between different ethnic groups, environmental factors such as calcium intake, vitamin D status, hormonal status, body size, and total body bone mineral density have to be considered. Understanding the molecular physiology of the genes described in this article and all genes influencing bone metabolism identified in the future will enable us to identify persons at risk for osteoporosis and to develop more specific therapies.