Holoprosencephaly

What it means

Holoprosencephaly is a structural anomaly of the brain in which the developing forebrain fails to divide into two separate hemispheres and ventricles.

The presence of a single cerebral ventricle (instead of the usual four) may be seen as part of holoprosencephaly.

Rare diseases that can present with this36

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Single brain ventricle