A large maternally inherited duplication of 14q and deletion of proximal 15q was observed in a child with myoclonic epilepsy, mental retardation and neuroblast migration disorders (NMDs) detected by MRI. Genetic syndromes associated with NMDs have previously been described. In additional our observations support the connection between major chromosomal imbalances, developmental brain disorders and epilepsy. Thus, in patients with these combinations of symptoms, careful chromosome investigations are recommended.