Heterogeneous seizure manifestations in Hypomelanosis of Ito: report of four new cases and review of the literature.

Hypomelanosis of Ito (HI) is a rare neuroectodermal disorder often associated with mental retardation and epilepsy. We report on four new HI patients presenting with heterogeneous seizure manifestations and we review the literature concerning epileptic seizures in HI. At one extreme, there are patients with generalized seizures well controlled by drug treatment, whereas at the opposite there are patients with severe, often pharmacoresistant, focal seizures. The genetic substrate for HI syndrome is not homogenous and only partially understood. Further researches are required to shed light on the pathogenesis of HI phenotypes.