Genetic determinants of susceptibility to osteoporosis.

Osteoporosis has a strong genetic component, and clinical studies have shown that heritable factors play a key role in regulating bone mineral density, ultrasound properties of bone, skeletal geometry, and bone turnover and contribute to the pathogenesis of osteoporotic fracture. In most cases, osteoporosis is caused by the combined effects of several different genes and their interaction with environmental influences, but it can occasionally occur as the result of mutations in a single gene. Genes that have been implicated in the regulation of bone mass in humans include the genes encoding lipoprotein receptor-related protein 5, sclerostin, transforming growth factor beta-1, collagen Ialpha1, vitamin D receptor, tumor necrosis factor receptor 2, and the estrogen receptor alpha. From a clinical standpoint, advances in knowledge about the genetic basis of osteoporosis are important because they offer the prospect of developing genetic markers for the assessment of fracture risk and the opportunity to identify molecules that will be used as targets for the design of new drugs for the prevention and treatment of bone disease.