Ambulatory adults with epilepsy and chronic treatment with AEDs are at greater risk of metabolic osteopathy as evidenced by osteopenia/osteoporosis, fracture, hypocalcemia, and hypovitaminosis D. The metabolic bone loss and mineral abnormalities are associated with accelerated bone turnover as evidenced by higher levels of sRANKL and sRANKL/OPG ratio and lower levels of OPG (markers of bone remodeling). The gene discussed is TNFRSF11B; the disease is rickets.