Infantile SVT in Consequence of a Congenital Antithrombin Deficiency

Abstract 5260

The liver-made antithrombin is a natural coagulation inhibitor in human blood. Exceptionally it takes effect in inhibiting the coagulation-supporting factors IIa (thrombin) and Xa. A congenital antithrombin deficiency leads to thrombosis and has to be heterozygous, because homozygous ATIII deficiencies are incompatible with life. Unfortunately it's dominant inherited.

In 1965 a congenital ATIII deficiency was first detected as a hereditary disease. There are two different types, type I describes a less produced ATIII deficiency, type II is a function loss of ATIII. Special testing can define more subclasses.

In cases of congenital ATIII deficiency, vascular blockage (thrombosis) appears, especially in leg veins. Released clots can cause pulmonal embolism, rarely are other arteries affected.

Although this disease is hereditary, it appears mostly between ages of 15 'til 30. Clinical trials showed that 80% of affected patient have a thrombosis or embolism until the age of 40. Has there be no kind of illness appeared until there, it's very improbable to get one becaus eof ATIII deficiency.

Every hundredth below the age of 70, who comes to a health care center has a ATIII deficiency. In total population it's a freqzuency of 1:2000 until 1:5000. Mostly there's a deficiency nown in familary history why they are investigated. The residual activity is between 40 – 60%.