Myocardial infarction in a neonate with hereditary antithrombin III deficiency.

We report the case of a newborn girl with antithrombin III deficiency type 1. The clinical features of a hypercoagulable condition that lead to this rare diagnosis differed from the reports in the literature, since the primary thromboembolic incident resulted in neonatal myocardial infarction, which is in itself a rare condition during the first days of life.