Acidosis decreases expression of osteoblastic extracellular matrix proteins, including type 1 collagen,(7,8) osteopontin, and matrix gla protein,(11,12) and increases expression of COX-2(10) and RANKL.(9,13) Acidosis also increases secretion of osteoclastic β-glucuronidase.(8). The gene discussed is SPP1; the disease is Acidosis.