Deficit of a protein With
Contents:
Description:
The protein With - natural anticoagulant, a glycoprotein, dependent on vitamin K, is synthesized in a liver in an inactive form.
The activated protein With - serinovy protease which function is directed to an inactivation of factors of Va and VIIIa, the important regulator of activity of thrombin on an endothelium surface. The protein With is activated at interaction of thrombin with thrombomodulin. This communication accelerates formation of thrombin in a form of the activated S. Aktivnost's protein of a protein With amplifies its cofactor - S protein. The activated protein With proteolytic inactivates factors of Va and VIIIa in the presence of a protein of S, phospholipid (an endothelium surface) and calcium, inhibiting further activation of thrombin.
Normal protein level With makes 65–145%. At pregnancy it raises a little and makes 70–150%, even more it raises in a puerperal period.
Symptoms of Deficit of a protein With:
- usual loss of pregnancy, a still birth, fruit losses (to 27,9%);
- venous fibrinferments and thromboembolisms at the age of 20–30 years of any localizations;
- necroses of skin, hypodermic cellulose (especially at treatment by indirect anticoagulants);
- increase in risk of thromboses at use of oral contraceptives;
- practical absence of arterial thromboses.
The reasons of Deficit of a protein With:
Inborn deficit of a protein With is caused by a gene mutation. The protein gene With is located on a chromosome 2. More than 150 mutations of a gene are known. Very often deficit of a protein With is combined with a mutation of a factor of V.
Deficit of a protein With is met a little more often than deficit of antithrombin III, among patients with fibrinferments and thromboembolisms this pathology is noted approximately at 10% of patients.
Deficit of a protein With is inherited autosomal is prepotent. Protein level With at heterozygous carriers is equal to 30-60% of norm, homozygous have practically no protein With and perish vnutriutrobno or right after the birth.
Hereditary deficit of a protein With can be 2 types:
* The I type - decrease in quantity of a protein With;
* The II type - decrease of the activity of a protein With at its normal level.
Disturbances in system of a protein With
Treatment of Deficit of a protein With:
Patients with heterozygous deficit of a protein With at acute fibrinferments have to receive heparin, and later - to pass to indirect anticoagulants. At the same time, however, it is necessary to remember that indirect anticoagulants can reduce level not only a factor of II, a factor of VII, a factor of IX and a factor of X, but also a protein With that will nullify its antitrombotichesky action. Considering at the same time the fact that deficit of a protein With contributes to development of varfarinovy necroses of skin.
At homozygous deficit of a protein With for prevention of thromboses and the IDCS instead of indirect anticoagulants periodic plasma transfusions are used.
