Clonal Hematopoiesis and NETs Formation in Venous Thrombosis (CLODETTE)

Inclusion Criteria: * Patients (male or female) less than 50 y.o with : * Splanchnic venous territory thrombosis or * Cerebral venous thrombosis or * Venous thrombosis of the upper limb or * Pulmonary embolism (1st episode if male, 2nd episode if female) unprovoked or * 1 episode of deep vein thrombosis + 1 episode of arterial thrombosis Exclusion Criteria: * Presence of a major or minor transient venous thrombosis risk factor: * Surgery within the last 3 months preceding the qualifying thrombotic episode * Lower limb fracture with immobilization \> 3 days in the last 3 months preceding the qualifying thrombotic episode * Presence of estro-progestational contraception * Pregnancy * Immobilization for acute medical reasons within the last 3 months preceding the qualifying thrombotic episode * Air or car travel \> 6 hours * Presence of a major or minor persistent risk factor for venous thrombosis: * Presence of active cancer (solid cancer or hematologic malignancy) * Chronic inflammatory digestive or joint diseases * Ongoing treatment with heparin (low molecular weight heparin (LMWH) or unfractionated heparin (UFH)) * Presence of an abnormality on the thrombophilia test among the following abnormalities * Protein C deficiency * Protein S deficiency * Anti-thrombin deficiency * Heterozygous or homozygous factor II mutation * Heterozygous or homozygous factor V mutation * Presence of anti-phospholipid syndrome * Presence of myeloproliferative neoplasia * Presence of paroxysmal nocturnal hemoglobinuria