Quantitative fibrinogen disorders, including afibrinogenemia and hypofibrinogenemia, are defined by the complete absence or reduction of fibrinogen, respectively. The diagnosis is based on the measurement of fibrinogen activity and antigen levels, which define the severity of this monogenic disorder. Afibrinogenemia is the result of homozygosity or combined heterozygosity for the causative mutations, whereas monoallelic mutations lead to hypofibrinogenemia. The bleeding phenotype varies …