Rare diseases · Sign or symptom

Abnormality of the anterior commissure

HP:0030301

What it means

An anomaly of the anterior commissure, a bundle of nerve fibers that connect the two cerebral hemispheres across the midline. The anterior commissure plays a role in pain sensation and contains decussating fibers from the olfactory tracts.

The human brain commissures comprise the corpus callosum, the anterior commissure, the fornix, and the posterior commissure.

Rare diseases that can present with this1

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

Abnormality of the anterior commissure

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This page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.