The patient is a 54-year-old male with a history of recurrent, asymptomatic ischemic stroke or transient ischemic attack (TIA) since age 14 and four episodes of deep vein thromboses (DVT), two complicated by pulmonary embolism, attributed to hereditary protein S deficiency and homozygous factor V Leiden mutation. Here, PROS1 is linked to deep vein thrombosis.