Abstract

Hemimegalencephaly (HME), or unilateral megalencephaly, is a rare congenital disorder affecting all or a part of a cerebral hemisphere.

Pathophysiology

It is a disorder related to excessive neuronal proliferation and hamartomatous overgrowth affecting the cortical formation. The excessive proliferation is postulated to occur early and to possibly continue beyond the normal proliferative period. Epidermal growth factor is thought to play an important role in the excessive proliferation and the pathogenesis of HME.

Genetics

Somatic activation of AKT3 causes hemispheric developmental brain malformations.