Matrix Gla protein (MGP) is is a vitamin K-dependent,extracellular matrix protein. MGP plays a pivotal role in preventing soft tissue calcification and local mineralization of the vascular wall. Vitamin K deficiency leads to inactive uncarboxylated MGP (ucMGP),which accumulates at sites of arterial calcification. However MGP is synthesized in many tissues and is especially enriched in embryonic tissues and in cancer cells. Defects in MGP are the cause of Keutel syndrome (KS),which is an autosomal recessive disorder characterized by abnormal cartilage calcification,peripheral pulmonary stenosis neural hearing loss and midfacial hypoplasia.