All participants had a thrombotic workup that included the following: genetic markers: factor V Leiden G1691A and G20210A prothrombin mutations, methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms; protein assays: protein C, protein S and antithrombin; other tests: blood typing and screening for hyperhomocysteinemia.
These include a group of mostly autosomal dominant, inherited gene mutations leading to a hypercoagulable state, such as factor V Leiden G1691A, factor II or prothrombin G20210A, and hyperhomocysteinemia associated with methylenetetrahydrofolate reductase C677T mutation.
We calculated the prevalences of prothrombin G20210A, factor V G1691A (also associated with high risk for DVT) and homozygous methylenetetrahydrofolate reductase (MTHFR) C677T (associated with increased susceptibility to develop hyperhomocysteinemia) in 118 patients with a first episode of DVT and in 416 healthy controls.
Controlled data on the association of MTHFR genotypes, hyperhomocysteinaemia and their interaction with factor V G1691A with childhood thrombosis are not yet available.