Cyclopia with Proboscis in Alobar Holoprosencephaly—A Rare and Lethal Craniofacial Malformation: A Case Report

Holoprosencephaly (HPE) is a developmental anomaly caused by incomplete division of the forebrain during early gestation.Alobar HPE, the most severe form, is associated with craniofacial anomalies such as cyclopia and a proboscis and is incompatible with life.We report a case of a 21-year-old gravida 2 para 1 at 14 weeks and 6 days of gestation, with no history of teratogenic exposure.Prenatal ultrasonography revealed a single cerebral ventricle, fused thalami, absence of midline brain structures, and facial malformations.The pregnancy was medically terminated at 16 weeks.The expelled fetus confirmed the sonographic diagnosis, with no other gross anomalies.Though genetic analysis was declined, recurrence risk and the importance of periconceptional folic acid supplementation were discussed for future pregnancies.This case underscores the utility of first-trimester ultrasound in identifying lethal congenital anomalies, allowing timely intervention and reproductive counseling.