The Role of Antenatal Ultrasound Scans in the Early Detection of Alobar Holoprosencephaly: A Case Report.

Holoprosencephaly (HPE) is a developmental defect that affects the brain structure due to failure or incomplete division of the prosencephalon at the third week to the fourth week of gestation into cerebral hemispheres. Although the exact cause of HPE remains unclear, it is suspected to result from a combination of genetic and environmental factors. We report a case of alobar HPE. This case was diagnosed on antenatal ultrasonography in a 42-year-old female (Gravida 3, Para 2) with an unremarkable family history and absence of any risk factors. The association of alobar HPE with an atrioventricular canal defect, left-sided clubfoot, and omphalocele, in this case, constitutes a rare fetal morphological presentation. This case highlights the crucial role of regular antenatal ultrasound scans in the early detection of fatal anomalies like alobar HPE.