Objective: Malformations of cortical development (MCD) are rare central nervous system abnormalities that are caused by disruption of normal cortical development stages, including neural cell proliferation, cell type differentiation, neuronal migration, and final neuronal positioning. It has different phenotypic presentations which largely depend on the underlying cause of the disorder and is associated with other neurologic and systemic disorders. MCD frequently present with seizures, various degrees of developmental delay, and intellectual disability.

Material and Methods: The findings of clinical, laboratory, electrophysiological, and magnetic resonance imaging of thirty-six patients
diagnosed with MCD in the last five years have been reported. Responses to drug therapies in epileptic patients and phenotypic
expressions in patients with the genetically proved mutation were also reviewed.

Results: Developmental delay, intellectual disability, and seizures (%72) were the main clinical findings. MCD has been recognized with
magnetic resonance imaging in all patients. Diffuse cortical malformations have been detected in a third of our patients. Single and/or
multiple brain lobe involvements have been determined in other patients. Congenital muscular dystrophy was the most diagnosed disease
in the patients who had elucidated with genetic tests.

Conclusion: Seizures, developmental delay, and intellectual disability could be caused by many disorders including MCD. The type and
diffusiveness of the MCD, associated neurologic and systemic findings should be accurately evaluated. Recent developments in genetic
methods have improved the accurate diagnosis, prognosis prediction, and treatment planning strategies in patients with MCD.

Keywords: Epilepsy, Malformations of cortical development, Motor and cognitive retardation