Although there are insufficient studies investigating the coexistence of FV Leiden variant (p.Arg506Gln) and CFDs, a reported case of heterozygous dysfibrinogenemia (FGG, p.Arg275Cys) carrying the FV Leiden variant suggests that this combination may increase the risk of thromboembolic events, notwithstanding that most cases with the p.Arg275Cys variant do not experience clinical thrombotic disorders [69]. Here, F5 is linked to thrombotic disease.