Premature closure of foramen ovale and renal vein thrombosis in a stillborn twin homozygous for methylene tetrahydrofolate reductase gene polymorphism: A clinicopathologic case study

Premature closure of the foramen ovale, 4-chamber cardiac hypertrophy, and renal vein/vena cava thrombosis were found at autopsy of a stillborn dizygo tic twin at 36 weeks gestational age. Review of the original prenatal sonog rams showed features suggestive of early closure of the foramen ovale. Homo zygosity for the 5,10 methylene tetrahydrofolate reductase mutation was sho wn only in the affected twin after the parents were found to be heterozygou s for the mutation. The difference in outcome of the twins following prenat al treatment with beta mimetics and corticosteroids for preterm labor may b e related to the added susceptibility factor for thromboembolism associated with presumed hyperhomocysteinemia in the proband which was nor shared by the surviving healthy twin. The role of premature closure of the foramen ov ale and prenatal treatment an discussed but remain uncertain.