Double cortex, also known as subcortical laminar heterotopia, is characterised by the presence of a band of neurons below the cortex. It mainly affects females, but in rare cases has also been reported in males. Affected individuals typically present with epilepsy with variable degrees of learning difficulties.
In most instances the syndrome is a result of mutations in a gene called DCX, but has also been attributed to mutations in LIS1. These mutations are usually sporadic, although in some cases they may be inherited from a parent.