Right ventricle hypertrophy in fetuses diagnosed with Noonan syndrome: Can ductus venosus agenesis represent a contributing cause?

Noonan syndrome (NS) is the most common genetic syndrome in fetuses with increased nuchal translucency (NT) and normal karyotype. NS patients present typical patterns of cardiac defects, such as pulmonary stenosis, polyvalvular dysplasia and hypertrophic cardiomyopathy. This study aims to evaluate onset and trend of cardiac disease in fetuses with molecular diagnosis of NS and to search for other cardiovascular sonographic markers of NS. We performed a fetal echocardiographic follow-up of pregnancies with increased NT in the first trimester. All the fetuses with normal Karyotype and Comparative Genomic Hybridizationarray underwent a targeted next-generation sequencing panel for RASopathies. Increased NT was the only finding up to the second trimester in half of the fetuses, while in the others ductus venosus agenesis was also observed. In all of them, during the late second trimester, a severe cardiopathy arouse.