Alobar Holoprosencephaly

This developmental disorder occurs when the embryonic forebrain, or prosencephalon, fails to undergo the typical division into right and left cerebral hemispheres during early fetal growth. In cases of Alobar Holoprosencephaly, the brain remains a single, undivided structure, which is typically associated with significant neurological and facial abnormalities.

As the most severe classification of holoprosencephaly, this condition is defined by a complete lack of midline brain division. It is clinically distinguished from less severe forms, such as semilobar or lobar holoprosencephaly, by the total absence of a longitudinal fissure and the presence of a single, unified cerebral lobe.