Thrombus obstructing the right ventricle outflow tract in a neonate with methylenetetrahydrofolate reductase 677TT genotype

At her first day of life, a neonate presented with severe cyanosis and a mass obstructing the right ventricle outflow tract. Prostagladin E1 was necessary to provide pulmonary blood flow. The mass was removed using extracorporeal bypass surgery; the right ventricle was dilated, and the pulmonary valve leaflets were damaged. Sternal closure was delayed because of bleeding and poor cardiac performance. Histology demonstrated that the mass was a mixed thrombus. Investigation revealed homozygous 677TT genotype of the methylenetetrahydrofolate reductase. In conclusion, a life-threatening thrombotic event such as an intracardiac thrombus obstructing the right ventricle outflow tract can occur in a neonatal age. Since the event can be a result of a combination of acquired and congenital thrombogenic risk factors, an extensive screening including DNA-based mutation analysis should be performed.