What vitamin deficiency contributes to liver-related bleeding disorders?

Vitamin K is essential for the hepatic synthesis of several coagulation factors, specifically Factors II (prothrombin), VII, IX, and X, as well as the anticoagulant proteins C and S. These factors require vitamin K as a cofactor for a post-translational modification called gamma-carboxylation, which allows them to bind calcium and become functional. When the liver is diseased or when vitamin K is deficient, production of these clotting factors is impaired, resulting in a prolonged prothrombin time and increased bleeding risk. This is why patients with liver disease commonly have coagulopathy. Vitamin A deficiency causes night blindness and epithelial dysfunction but does not directly impair coagulation factor synthesis. Vitamin C deficiency leads to scurvy, which causes capillary fragility and poor collagen synthesis, resulting in bleeding from gums and petechiae; however, this is not a liver-related coagulation factor deficiency. Vitamin D deficiency is associated with bone metabolism disorders and immune dysfunction, not coagulation factor production. The liver-specific connection makes vitamin K the most clinically relevant answer in the context of liver-related bleeding disorders, and it is also the basis for warfarin's mechanism of action as a vitamin K antagonist.