alpha-2-HS-glycoprotein also known as fetuin-A belongs to the fetuin class of plasma binding proteins and is more abundant in fetal than adult blood. Alpha2-HS glycoprotein is synthesized by hepatocytes and adipocytes. It is involved in several functions, such as endocytosis, brain development and the formation of bone tissue. The mature circulating AHSG molecule consists of two polypeptide chains, which are both cleaved from a proprotein encoded from a single mRNA. AHSG is a secreted partially phosphorylated glycoprotein with complex proteolytic processing that circulates in blood and extracellular fluids. Fetuins are carrier proteins like albumin. Fetuin-A forms soluble complexes with calcium and phosphate and thus is a carrier of otherwise insoluble calcium phosphate. Thus fetuin-A is a potent inhibitor of pathological calcification, in particular Calciphylaxis. High levels of Fetuin-A are associated with obesity and insulin resistance.