Doublecortin (DCX) is a member of the doublecortin family, which contains two doublecortin domains that can bind to microtubules. It plays a crucial role in brain development by regulating the organization and stability of microtubules, which are essential for neuronal migration. It is expressed widely by migrating neurons and is involved in guiding neuronal migration during the development of the cerebral cortex. DCX is critical for the migration of neurons to their final positions in the developing cortex. Mutations in DCX lead to abnormal migration of neurons and disrupt the layering of the cortex, which can result in epilepsy, cognitive disability, subcortical band heterotopia ("double cortex" syndrome) in females, and lissencephaly ("smooth brain" syndrome) in males. DCX is a microtubule-associated protein that can regulate microtubule dynamics. It has been shown to stabilize microtubules in the peripheral region of the growth cone, reducing the frequency of microtubule catastrophes and disassembly rates. Mutations in the DCX are associated with X-linked neuronal migration defects, including lissencephaly and double cortex syndrome. These conditions are characterized by the abnormal development of the cerebral cortex and can lead to severe neurological impairments.