The mutation we found in THBD (p.Pro501Leu) is an already-described variant with uncertain significance in the context of thrombomodulin-related disorders; however, as thrombomodulin not only regulates thrombus formation but also complement factor I-induced C3b inactivation, its association with CTEPH may be relevant [47,48]. The gene discussed is THBD; the disease is chronic thromboembolic pulmonary hypertension.