[4][5][6] Fetuin-A belongs to the fetuin class of plasma binding proteins and is more abundant in fetal than adult blood.

The protein is commonly present in the cortical plate of the immature cerebral cortex and bone marrow hemopoietic matrix, and it has therefore been postulated that it participates in the development of the tissues.

The mature circulating AHSG molecule consists of two polypeptide chains, which are both cleaved from a proprotein encoded from a single mRNA.

[8] Thus AHSG is a secreted partially phosphorylated glycoprotein with complex proteolytic processing that circulates in blood and extracellular fluids.

In the test tube AHSG can bind multiple ligands and therefore has been claimed to be involved in several functions, such as endocytosis, brain development and the formation of bone tissue.