A rare case of trisomy 13 mosaicism with only findings on first-trimester ultrasound single umbilical artery and increased nuchal translucency.

Background: Trisomy 13 is a chromosomal defect with high prenatal and postnatal mortality that may reach 87 % during the first year of life. More than 90 % of cases of fetuses with trisomy 13 may be detected by first-trimester ultrasound based on severe fetal structural malformations together with increased nuchal translucency thickness.

Case description: We report a case of a fetus with trisomy 13 mosaicism with only anomalous findings on prenatal ultrasound of a single umbilical artery and increased nuchal translucency in the absence of major structural abnormalities.

Conclusion: This case highlights the importance of performing first-trimester fetal ultrasound by specialists in Fetal Medicine to avoid misdiagnosis. Trisomy 13 should be included in the differential diagnosis and prenatal counseling in cases with a single umbilical artery and increased fetal nuchal translucency, even in the absence of major anatomic anomalies. HIPPOKRATIA 2024, 28 (1):38-40.