This gene encodes a glycoprotein coagulation factor that plays a critical role in the process of blood coagulation and hemostasis. The encoded protein is activated by thrombin, to generate a heterodimer containing heavy and light chains held together by calcium ions. About half of the mice lacking the encoded protein die at an embryonic stage possible due to abnormal yolk-sac vasculature while the remaining animals succumbed to massive hemorrhage immediately after birth. A point mutation in this gene has been shown to cause disseminated intravascular thrombosis in the perinatal period, resulting in frequent deaths of newborn mice. [provided by RefSeq, Apr 2015]