Lissencephaly

Lissencephaly, which means “smooth brain” is a spectrum of severe and rare brain malformations characterized by the lack of normal convolutions (folds) in the brain and microcephaly (a few cases) that affects developing fetuses. It is an abnormality of cortical development associated with deficient neuronal migration (the process in which nerve cells move from their place of origin to their permanent location) during embryonic development between 12 and 24 weeks of gestation and abnormal formation of cerebral gyri (the surface of a normal brain is formed by a complex series of folds and grooves). The folds/bumps are called gyri or convolutions, and the grooves/indentations are called sulci. In children with lissencephaly, the nor-mal convolutions are absent or only partly formed, making the surface of the brain smooth). Gyri and sulci are important because they increase your brain’s surface area (and thus cognitive ability) and separate brain regions.