An estimated 44 million Americans - many of whom are women - have or are at risk for osteoporosis, a disease in which the bones lose density and become prone to painful and debilitating fractures. Although scientists know that many genes influence bone mass and thus osteoporosis risk, identifying specific genes has been challenging - especially in humans, who are genetically diverse.

By using laboratory mice, whose bone physiology is similar to humans, however, NIAMS-supported researchers have been able to locate a gene that not only influences bone density in mice, but also provides new insight into how to preserve bone mass in people.

Robert Klein, M.D., of the Oregon Health and Science University in Portland, and his colleagues identified the gene, called Alox15, while working with two strains of mice that have very different bone mineral densities. Variations in the gene, they discovered, account for a significant part of that difference. While scientists have known of the gene for some time, it was never recognized as important for the skeleton. Instead, it was known to be involved in the metabolism of certain fats and was believed to play a role in heart disease and other health problems.

Because there are two genes in people with activities similar to that of Alox15, scientists believe that one or both of these genes might be targets for treatment of osteoporosis. Also, the discovery of Alox15's influence on bone mass suggests that a previously unsuspected metabolic pathway could be important for skeletal health, the researchers say. By further studying this pathway, scientists may find additional clues to the prevention of osteoporosis and the resulting fractures.

The mission of NIAMS, a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases, the training of basic and clinical scientists to carry out this research, and the dissemination of information on research progress in these diseases. Information on osteoporosis is available from the NIH Osteoporosis and Related Bone Diseases~National Resource Center; phone toll-free 800-624-BONE (2663), or visit https://www.bones.nih.gov/health-info/bone/osteoporosis. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at http://www.niams.nih.gov.

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Klein RF, et al. Regulation of bone mass in mice by the lipoxygenase gene Alox15. Science 2004;303(5655):229-232.