The best-known gene associated with polymicrogyria and microcephaly is WDR62, and germline or somatic variants in genes encoding components of the mTOR pathway, such as PIK3CA and PIK3R2, are usually associated with megalencephaly, often with other abnormalities such as vascular skin lesions and digital anomalies121. This evidence concerns the gene PIK3R2 and polymicrogyria.