Cortical dysplasia is a condition present at birth (congenital) that occurs when the neurons in the top layer of the brain (cortex) develop abnormally. This causes the neurons to fire abnormally, causing seizures. Other causes of cortical dysplasia may include genetic disorders or brain injuries. Cortical dysplasia is the most common cause of epilepsy (seizures).
The most common type of cortical dysplasia is focal cortical dysplasia (FCD), which is categorized into three types:
Type 1 focal cortical dysplasia causes seizures that do not appear until adulthood, and usually involves the brain’s temporal lobe.
Type II focal cortical dysplasia is found more frequently in children, involves the brain’s temporal and frontal lobes, and is more severe.
Type III focal cortical dysplasia involves damage to another part of the brain, possibly from an early brain injury, in addition to Type 1 or Type II.