(G20210/A of the prothrombin gene mutation)

Not to be confused with the mutation in the factor V of Leyden, another cause of thrombophilia.

This hereditary thrombophilia is the most frequent after the thrombophilia caused by the mutation of the factor V of Leyden. Recessive autosomal transmission of a mutation of the F2 gene (11p11-12) (substitution of guanine by adenine on the 20210 A nucleotide in the non transcribed 3' region of the gene) responsible for the synthesis of prothrombin. Factor II fonctions are retained, but the mutation induces a higher level of factor II than normal: most subjects carrying the mutation are in the highest quartile of factor II levels (> 115 %). In adults, the risk of thrombosis is multiplied by 3 in heterozygous and 6 in homozygous. In the current state of knowledge, it seems likely that this anomaly needs to be associated with other anomalies, or with special circumstances to induce a thrombotic disease. Homozygous forms appear to be rare, and there is little data on their clinical manifestations. 

This disease is expressed in very variable ways: many people with heterozygous or homozygous mutation never develop thrombosis while some others present with recurrent thrombosis before 30 years of age. In adults, this mutation often causes venous thrombosis in the lower limbs or pulmonary emboli .

Screening is not based on coagulation tests. The diagnosis can be only achieved by molecular biology technique, on the patient's DNA.

Anesthetic implications: 

perioperative thromboprophylaxis from adolescence

References : 

Updated: August 2019