Abstract
A case of extensive deep venous thrombosis in a four a day old infant was presented. Unusually this patient was shown to be heterozygous for three thrombophilia genes; Factor V Leiden, prothrombin and antithrombin gene mutations, the latter being novel.
There are no randomized controlled trials to guide management in deep venous thrombosis in the newborn but knowledge of the prothrombotic risk factors may help direct treatment.