Introduction: The prothrombin gene variant G20210A was first described as a risk factor for deep vein thrombosis, and recently for cerebral venous thrombosis, although reported cases had other concomitant risk factors.
Clinical cases: A 33 years old woman, with no previous vascular nor thrombotic risk factors, was admitted with thrombosis of superior longitudinal, lateral and sigmoid right sinus. The father had deep venous thrombosis 3 years before. One year later, the 29 year old sister of the proband, developed massive deep venous thrombosis, when she was 8 months pregnant. Laboratory investigations showed elevated anticardiolipin antibodies titer in the proband. Prothrombin activity was in the normal range in the 3 patients. Prothrombin gene mutation G 20210A was detected in the 3 patients.
Conclusion: As the presence of more than one thrombophilic factor (in the reported case, prothrombin G20210A mutation and anticardiolipin antibodies) increases the likehood of a thrombotic event, it is useful to screen for thrombotic genetic conditions, even when other vascular risks are present, and vice versa.