FGB and complement factor I deficiency: The literature describes five heterozygous nonsense mutations related to hypofibrinogenemia in C-terminal domains of the Bβ chain (Gln339, Gln393, Trp402, Cys407, and Trp440) [26,27,28,29,30], mostly located in the exon 8 of FGB. In four genetic variants the clinical phenotype was severe bleeding, similar to those typically observed in patients with afibrinogenemia, such as epistaxis, umbilical cord bleeding, splenic rupture, and intracranial hemorrhage, but also milder manifestations, as described in our two patients.