{Reference Type}: Case Reports {Title}: Early-onset Marfan syndrome with aortic dilatation and giant pulmonary artery aneurysm: A case report. {Author}: Zhang QN;Xu FL;Shi SS; {Journal}: Turk Gogus Kalp Damar Cerrahisi Derg {Volume}: 32 {Issue}: 1 {Year}: 2024 Jan {Factor}: 0.704 {DOI}: 10.5606/tgkdc.dergisi.2024.24850 {Abstract}: A 30-year-old woman with ankylosing spondylitis was referred to our clinic with abnormal fetal echocardiography findings, including ascending aortic dilatation, giant main pulmonary artery aneurysm, and aortic and pulmonary valve stenosis at 22 weeks of gestation. The full-term male neonate was born by cesarean section and was transferred to the cardiac intensive care unit soon after delivery for respiratory distress with low percutaneous oxygen saturation. Based on cardiovascular and genetic analysis findings, the patient was diagnosed with Marfan syndrome. Surgery was performed; however, the patient died due to cardiac arrest. In conclusion, main pulmonary artery dilatation and aneurysms are uncommon in Marfan syndrome; therefore, presentation with these findings during the fetal life, as in the present case, is likely a sign of severe Marfan syndrome-related cardiac involvement.