Abstract
Noonan Syndrome (NS) is a genetic disorder characterized by distinctive facial features, congenital heart defects (CHD), and other anomalies. Umbilical-portal-systemic venous shunt (UPSVS) is a rare vascular anomaly detectable prenatally. We report two cases of NS associated with UPSVS. The first case was referred at 31 weeks of gestation for fetal cardiomegaly and ductus venosus agenesis, with the umbilical vein draining into the inferior vena cava. Postnatal findings included CHD, dysmorphic features, and a mediastinal neuroblastoma. Genetic testing confirmed NS. The second case, was referred at 29 weeks of gestation for multiple fetal anomalies, presented with hydrops and type I UPSVS on ultrasound and fetal MRI. A pathogenic variant in the PTPN11 gene was identified. The neonate died shortly after birth. These cases suggest that fetal UPSVS should raise suspicion for RASopathy; hence, improving prenatal recognition of NS and informing clinical management should be performed.
References
Roberts AE, Allanson JE, Tartaglia M, Gelb BD. Noonan syndrome. Lancet. 2013;381(9863):333-342.
Roberts AE. Noonan Syndrome [abstract]. GeneReviews [serial online]. 1993–2025. Available at: https://www.ncbi.nlm.nih.gov/books/NBK1124/#noonan.Differential_Diagnosis Accessed June 18, 2025.
Rauen KA. The RASopathies. Annu Rev Genomics Hum Genet. 2013;14:355–369.
Pacheco D, Brandão O, Montenegro N, Matias A. Ductus venosus agenesis and fetal malformations: what can we expect? – a systematic review of the literature. J Perinat Med. 2019;47(1):1–11.
Achiron R, Kivilevitch Z. Fetal umbilical-portal-systemic venous shunt: in-utero classification and clinical significance. Ultrasound Obstet Gynecol. 2016;47(6):739–747.
Mutesa L, Pierquin G, Janin N, et al. Germline PTPN11 missense mutation in a case of Noonan syndrome associated with mediastinal and retroperitoneal neuroblastic tumors. Cancer Genet Cytogenet. 2008;182(1):40–42.
Sokollik C, Bandsma RH, Gana JC, van den Heuvel M, Ling SC. Congenital Portosystemic Shunt: Characterization of a Multisystem disease. J Pediatr Gastroenterol Nutr. 2013;56(6):675–681.
Jacquier M, Dumery G, Bault JP, Franchi S, Sénat MV. [Abnormalities of umbilical-portal circulation: from screening to diagnosis]. Gynecol Obstet Fertil Senol. 2019;47(12):860–871.
Franchi-Abella S, Branchereau S, Lambert V, et al. Complications of congenital portosystemic shunts in children: therapeutic options and outcomes. J Pediatr Gastroenterol Nutr. 2010;51(3):322–330.
Menashe M, Arbel R, Raveh D, Achiron R, Yagel S. Poor prenatal detection rate of cardiac anomalies in Noonan syndrome. Ultrasound Obstet Gynecol. 2002;19(1):51–55.
This work is licensed under a Creative Commons Attribution 4.0 International License.
Copyright (c) 2025 Camille, Patricia Steenhaut, Marie Laterre, Pierre Bernard