Rare diseases · Sign or symptom
Polymicrogyria
More grooves in brain
HP:0002126
What it means
Polymicrogyria is a congenital malformation of the cerebral cortex characterized by abnormal cortical layering (lamination) and an excessive number of small gyri (folds).
Polymicrogyria, one of the most common malformations of cortical development, is characterized histologically by the appearance of an excessive number of small cortical folds, often fused together, with disordered cortical lamination.
Rare diseases that can present with this51
Very common80–99%
10- 6q terminal deletion syndrome
- Aicardi syndrome
- Baraitser-Winter cerebrofrontofacial syndrome
- CK syndrome
- Lhermitte-Duclos disease
- Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome
- Oculocerebrocutaneous syndrome
- Polymicrogyria due to TUBB2B mutation
- Polymicrogyria with optic nerve hypoplasia
- Walker-Warburg syndrome
Common30–79%
12- Autosomal recessive cutis laxa type 2, classic type
- CEDNIK syndrome
- Chudley-McCullough syndrome
- Cortical dysgenesis with pontocerebellar hypoplasia due to TUBB3 mutation
- Hemimegalencephaly
- Microcephalic cortical malformations-short stature due to RTTN deficiency
- Microcephaly-polymicrogyria-corpus callosum agenesis syndrome
- Muscle-eye-brain disease with bilateral multicystic leucodystrophy
- Neu-Laxova syndrome
- Sub-cortical nodular heterotopia
- Subependymal nodular heterotopia
- Zellweger syndrome
Sometimes5–29%
23- Carnitine palmitoyl transferase II deficiency, neonatal form
- CLOVES syndrome
- Congenital fibrosis of extraocular muscles
- Congenital muscular dystrophy with cerebellar involvement
- Desmosterolosis
- Hypertelorism-hypospadias-polysyndactyly syndrome
- Isolated Joubert syndrome
- Joubert syndrome with ocular anomaly
and 15 more in this range
Rare1–4%
6The 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
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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.