F5 and interstitial lung disease: Although existing studies have found a low incidence of the coagulation factor V Leiden mutation in patients with CTD, and it is not possible to confirm whether there is a direct association between this mutation and the development of VTE in patients with CTD-ILD [141], patients with CTD-ILD who are positive for the coagulation factor V Leiden mutation should be highly vigilant for the development of VTE in the clinic, especially when the patients present with severe dyspnea.