Unprovoked Thrombosis in a Young Male Revealing a Rare Coexistence of Antiphospholipid Syndrome and Double Heterozygous MTHFR Mutation With Hyperhomocysteinemia

A case of acute pulmonary thromboembolism (PTE) in a 39-year-old male who presented with progressive dyspnea and left lower limb pain. Imaging studies confirmed extensive pulmonary and deep venous thrombosis. A hypercoagulability workup revealed primary antiphospholipid syndrome (APS) with positive lupus anticoagulant and beta-2 glycoprotein antibodies, along with a compound heterozygous methylenetetrahydrofolate reductase (MTHFR) mutation and hyperhomocysteinemia. This case highlights the significant thrombotic risk posed by the co-occurrence of APS and the compound heterozygous MTHFR mutation. Early identification of such overlapping thrombophilic conditions is crucial for prompt management and effective secondary prevention.