Subcortical band heterotopia is a condition in which nerve cells (neurons) do not move (migrate) to their proper locations in the fetal brain during early development. (Heterotopia means "out of place.") Normally, the neurons that make up the outer surface of the brain (cerebral cortex) are distributed in a well-organized and multi-layered way. In people with subcortical band heterotopia, some neurons that should be part of the cerebral cortex do not reach it. These neurons stop their migration process in areas of the brain where they are not supposed to be and form band-like clusters of tissue. Since these bands are located beneath the cerebral cortex, they are said to be subcortical. In most cases, the bands are symmetric, which means they occur in the same places on the right and left sides of the brain.

Mutations in the DCX or PAFAH1B1 gene cause subcortical band heterotopia. Both genes provide instructions for making proteins that are involved in the movement of neurons to their proper locations in the developing brain, a process called neuronal migration. Neuronal migration is essential for normal brain development and function.

More than 200 cases of subcortical band heterotopia have been reported in the scientific literature. Most affected individuals are female.

The inheritance pattern of subcortical band heterotopia depends on its genetic cause.

Published Date: April 01, 2019
Published By: National Institutes of Health