Sclerostin concentrations are increased in disorders such as hypoparathyroidism [13], type II diabetes [14, 15] cancer induced bone disease [16] and Paget’s disease [17] and decreased in primary hyperparathyroidism [18–20] and ankylosing spondylitis [21], although recently increased disease activity in ankylosing spondylitis has been associated with higher sclerostin concentrations [22]. The gene discussed is SOST; the disease is cancer.