The TMPRSS6 gene provides instructions for making a protein called matriptase-2.
This protein is part of a signaling pathway that controls the levels of another protein called hepcidin, which is a key regulator of iron balance in the body. When blood iron levels are low, this signaling pathway reduces hepcidin production, allowing more iron from the diet to be absorbed through the intestines and transported out of storage sites (particularly in the liver and spleen) into the bloodstream. Iron is an essential component of hemoglobin, which is the molecule in red blood cells that carries oxygen.
A high impact genetic variation in TMPRSS6 can lead to overproduction of hepcidin and, in turn, to defective iron absorption and utilization.