Previous studies on healthy individuals, individuals with endocrine disorders (such as Cushing's syndrome, thyrotoxicosis and primary hyperparathyroidism) or other skeletal diseases (such as heterotrophic pulmonary ostoarthropathy) have shown TSU of 99mTc-MDP to be correlated to conventional bone turnover markers such as osteocalcin, urinary deoxypyridinoline [18], total alkaline phosphatase, and urinary hydroxyproline [13,16-18] but data on many currently available, more specific and sensitive bone turnover markers has been lacking. The gene discussed is BGLAP; the disease is Cushing syndrome.