Rare diseases · Sign or symptom

Mild microcephaly

HP:0040196

What it means

Decreased occipito-frontal (head) circumference (OFC). For the microcephaly OFC must be between -3 SD and -2 SD compared to appropriate, age matched, normal standards (i.e. -3 SD <= OFC < -2 SD).

Rare diseases that can present with this9

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

Mild microcephaly

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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.