Fibrinogen has a double function: yielding monomers that polymerize into fibrin and acting as a cofactor in platelet aggregation.
Involvement in disease: Defects in FGG are a cause of thrombophilia.
Defects in FGG are a cause of congenital afibrinogenemia (CAFBN). It is a rare autosomal recessive disorder characterized by complete absence of detectable fibrinogen.