Postmortem DNA diagnosis of factor V Leiden in a neonate with systemic thrombosis and probable antithrombin deficiency.

BACKGROUND

Spontaneous neonatal thrombosis due to heritable gene defects has been reported in the past. A recently discovered defect, the factor V Leiden mutation, is the most frequent inherited risk factor for venous thrombosis.

CASE

Factor V Leiden was diagnosed postmortem in a neonate who died from complications of vena caval and aortic thrombosis. Investigation into the family history revealed that the father had a record of multiple thromboses, and blood testing demonstrated that the father had antithrombin deficiency and the mother was heterozygous for factor V Leiden. Although we were unable to demonstrate directly the presence of antithrombin deficiency in the infant, we propose that a combination of the two inherited disorders was likely the cause of fatal neonatal thrombosis.

CONCLUSION

The present report highlights the importance of a complete prenatal genetic analysis, including factor V Leiden testing and antithrombin measurement in families with a history of thrombotic disorders.