Prenatal Diagnosis of Alobar Holoprosencephaly With Cyclopia and Proboscis: A Case Report

Alobar holoprosencephaly (HPE) is a severe developmental abnormality of the fetal brain. It can also be associated with major facial abnormalities. We report a case diagnosed during a routine ultrasound scan at 22 weeks of pregnancy in a 26-year-old G2P1L1 woman. Ultrasound showed a single ventricular cavity, an absent interhemispheric fissure and falx cerebri, and fused thalami. Facial examination showed a single median orbit and a midline proboscis, consistent with cyclopia. No other structural abnormalities were seen. After counseling about the severe nature and poor prognosis of the condition, the pregnancy was terminated at 23 weeks. This case highlights the importance of examining the fetal face when alobar HPE is suspected on ultrasound.