Truncus Arteriosus With Absent Semilunar Valve: Prenatal Diagnosis and Morphology

Abstract Background：Truncus arteriosus (TA) is a rare cyanotic congenital heart defect that involves septation failure of the heart’s main arterial outflow tract. TA is usually accompanied by a single semilunar valve. Varying morphologies of the truncal valve have been reported; however, an absent semilunar valve (ASV) is rarely seen in TA.Case presentation：We report the first fetus with trisomy 13 prenatally diagnosed with TA accompanied by ASV in the first trimester, and confirmed by anatomy. Conclusion：Fetal echocardiography is essential for prenatal diagnosis of TA accompanied by ASV.