Holoprosencephaly can be categorized into four main types based on the severity and extent of the brain malformation:
Alobar HPE: The most severe form, characterized by a complete lack of separation between the cerebral hemispheres. Semilobar HPE: There is partial separation of the hemispheres, but they remain fused at the frontal areas. Lobar HPE: The least severe form, with significant separation of the hemispheres but some fusion, typically in the frontal lobes. Middle Interhemispheric Variant (MIH): A rare form where the fusion occurs in the middle part of the brain.
