Spontaneous venous thrombosis in a young patient with combined factor V Leiden and lupus anticoagulant.

We describe a case of a 28-year-old man who developed an extensive spontaneous deep venous thrombosis. Testing revealed heterozygotic factor V Leiden mutation, and the presence of both lupus anticoagulant (LA) and elevated IgM anticardiolipin antibody (ACA). Several family members were found to be heterozygous for factor V Leiden. A paternal aunt had the factor V Leiden mutation, an elevated plasma homocysteine and a borderline increased IgG ACA level. No other family member had a history of a venous thrombotic event. This case illustrates that evaluation of young patients who present with venous thrombosis should be performed for both hereditary and acquired thrombophilic defects. The family studies suggest that the presence of a lupus anticoagulant may be more clinically significant than elevated ACA in risk assessment. Although screening family members when the proband carries factor V Leiden is controversial, psychological reassurance of those who test negative and simple advice on occupations or social habits (e.g., smoking) for those who test positive may be important benefits.