Antithrombin iii deficiency primary hereditaryD68.5

Autosomal-dominant disorder of anticoagulation with increase of prothrombin fragments 1 and 2 in plasma.

A distinction is made:

• an antithrombin deficiency of type 1: activity and concentration are equally prevented.
• Type 2 antithrombin deficiency: the activity is reduced and the concentration normal or slightly increased.

The prevalence is 1 per 5000 in the population. Only heterozygous carriers are known.

Antithrombin III is an important regulator protein of plasmatic coagulation by inhibiting the serine kinases of the intrinsic system. The effect on the individual factors varies. Antithrombin III exerts the strongest inhibitory effect on thrombin and factor Xa.
The concentration in plasma is 0.14-0.39 g/l. The activity is 70-120% of the norm. Even a reduction of the antithrombin III activity to about 50% is associated with an increased coagulatory activity, which in turn is associated with an increased risk of thromboembolic events.

50% of feature carriers have already experienced thromboembolic complications before the age of 40. The thromboses mostly occur in the veins of the lower extremities. However, mesenteric and renal thromboses and thromboses of the vena cava also occur. Arterial thromboses have not been observed in cases of antithrombin deficiency.

In 1963 Egberg was the first to identify a disorder of AT-III as the cause of thrombophilia. 1983 the first specific mutation of antithrombin III was described. In the meantime, over 120 different mutations are known.

1. HA Neumann (2014) The coagulation system. ABW-Wissenschaftsverlag GmbH Berlin S. 223f.