Causes
Pachygyria is caused by a breakdown in the fetal neuronal migration process due to genetic or possibly environmental influences. The affected cerebral cortex will typically have only four developed layers instead of the normal six. One of the best known and most common types of neuronal migration disorders is lissencephaly, a diffuse cortical malformation relating directly to agyria and pachygyria. Incomplete neuronal migration during the early fetal brain development is the precursor to lissencephaly. Should neurons follow an abnormal migration during development possible cortical malformations include classical lissencephaly (as stated above) and subcortical band heterotopia with an agyria-pachygyria band spectrum.
Read more about this topic: Pachygyria