[Moderate deficiency of Factor XII associated with postoperative deep venous thrombosis].

The interrelationship between factor XII deficiency (Hageman trait) and thrombosis is well known. A case of moderate factor XII deficiency (activity, 30%) associated to deep vein thrombosis, which occurred in the popliteal region of the left lower limb after abdominal surgery, is reported. The deficit was found in 4 family members of the three generations studied, and all of them showed a close interrelationship between factor XII activity and kallikrein levels. Prolonged APTT was found in 3 of the 4 affected subjects. A multiallelic model is suggested to explain the genetic transmission of this impairment.