F5 and Venous thrombosis: If FVL heterozygotes and wild-type patients were compared within the group of ATBp3 heterozygotes, no significant differences were found in terms of the frequency of patients with thrombotic episodes (around 50%) and types of thrombosis (frequency of VT 44 and 45% for wild type and heterozygotes, respectively, PE 6% in both groups, ATE 10 and 6% for wild type and heterozygotes, respectively); however, heterozygotes were a bit younger at the time of the first symptoms.