Rare diseases · Sign or symptom
Hypoplasia of the brainstem
Small brainstem
HP:0002365
What it means
Underdevelopment of the brainstem.
This finding can be demonstrated by magnetic resonance imaging.
Rare diseases that can present with this21
Common30–79%
8- Cobblestone lissencephaly without muscular or ocular involvement
- Congenital muscular dystrophy with cerebellar involvement
- Cortical dysgenesis with pontocerebellar hypoplasia due to TUBB3 mutation
- DYRK1A-related intellectual disability syndrome due to 21q22.13q22.2 microdeletion
- Lissencephaly due to TUBA1A mutation
- Pontocerebellar hypoplasia type 2
- Pontocerebellar hypoplasia type 4
- Pontocerebellar hypoplasia type 7
Sometimes5–29%
12- Bilateral frontoparietal polymicrogyria
- Cerebellar-facial-dental syndrome
- DYRK1A-related intellectual disability syndrome
- Malan overgrowth syndrome
- Methylcobalamin deficiency type cblE
- Microcephaly-corpus callosum and cerebellar vermis hypoplasia-facial dysmorphism-intellectual disability syndrome
- Polymicrogyria with optic nerve hypoplasia
- Primary microcephaly-mild intellectual disability-young-onset diabetes syndrome
and 4 more in this range
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: Brainstem hypoplasia · Hypoplastic brain stem · Hypoplastic brainstem · Underdeveloped brainstem
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Start free with EleplanThis 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.