Australian scientists have found a single gene may influence risk of osteoporosis, suggesting a way to identify vulnerable people while young enough to take preventive steps. The disease, which affects 25 million Americans and causes 1.5 million fractures a year, has no early symptoms and is usually not diagnosed until after 50 when a fracture occurs. But if the finding is confirmed, a test may one day identify vulnerable people in childhood, when taking extra calcium might fortify their bones enough to avoid later fractures. In osteoporosis, bones deteriorate from excessive loss of tissue.
Fractures typically occur in the hip, spine, or wrist, but can appear in other bones.
Women are more susceptible. The research, reported in the journel Nature by Dr. John Eisman, Garvin Institute of Medical Research at St. Vincent's Hospital in Sydney, found the gene has a major effect on bone density, which has been shown to predict fracture risk. The gene tells the body how to make the receptor, or protein structure, that vitamin D uses to exert it's effect. Different versions of the gene were associated with different average bone densities. The vitamin D receptor plays a role in the absorption of calcium from food and in other processes involving calcium.