Common gene variants linked to osteoporosis

NEW YORK (Reuters Health) - Common variants in a gene called LRP5 affect bone density and the risk of developing the brittle-bone disease osteoporosis, according to a new study. However, the impact of these variants on risk is modest.

Previous research has identified genetic mutations in LRP5 (for LDL receptor-related proteins 5) that cause rare disorders associated with changes in bone mineral density. Whether common variants in the gene for LRP5 and, possibly LRP6, affect the risk of osteoporosis was unclear, however.

To investigate, Dr. John P. A. Ioannidis, from the University of Ioannina School of Medicine in Greece, and colleagues analyzed data from 18 centers in Europe and North America covering a total of 37,534 subjects. The investigators measured the participants' bone density and collected information on any fractures via questionnaires and medical records.

Two particular variants of LRP5 were associated with reduced bone density in the lower spine and hip, the team reports in the Journal of the American Medical Association.

Both genetic variants were also tied to an elevated risk of fractures, the report indicates.

The risks did not change markedly after adjusting for age, weight, height, menopausal status, and hormone therapy.

A variant of LRP6, by contrast, did not affect the risk of fractures, the researchers report.

They point out that finding a single marker provides only a small clue to the likelihood of developing osteoporosis, but "identification of several such osteoporosis risk variants may eventually help in improving clinical prediction."

SOURCE: Journal of the American Medical Association, March 19, 2008.