The Role of First-Trimester Ultrasound in Detecting Aortic and Pulmonary Valve Agenesis: A Rare Case of Trisomy 13.

Congenital Absent Pulmonary Valve Syndrome (APVS) is a rare heart defect often associated with other cardiac anomalies, with approximately 5.5% of cases related to trisomy 13. This case report describes a fetus with trisomy 13, presenting with the rare combination of absent pulmonary and aortic valves, along with an interrupted aortic arch. The patient was a 34-year-old pregnant woman with an otherwise normal pregnancy. At 12 weeks, ultrasound examination revealed thickened nuchal translucency (NT), ethmocephaly with proboscis, and a heart showing a single large vessel with alternating red and blue blood flow. Fetal autopsy confirmed the interrupted aortic arch and the absence of both valves. Chromosomal analysis revealed trisomy 13, supporting the genetic diagnosis. The combination of APVS with absent aortic valve and trisomy 13 is extremely rare, highlighting the importance of early prenatal diagnosis and genetic screening. Although the pregnancy ended in termination, early diagnosis allowed the family to understand the prognosis and make informed decisions, underscoring the critical role of ultrasound screening and genetic testing in prenatal diagnosis.