Periventricular heterotopia is a condition in which nerve cells (neurons) do not migrate properly during the early development of the fetal brain, from about the 6th week to the 24th week of pregnancy. Heterotopia means "out of place." In normal brain development, neurons form in the periventricular region, located around fluid-filled cavities (ventricles) near the center of the brain. The neurons then migrate outward to form the exterior of the brain (cerebral cortex) in six onion-like layers. In periventricular heterotopia, some neurons fail to migrate to their proper position and form clumps around the ventricles.
In most cases, periventricular heterotopia is caused by mutations in the FLNA gene. This gene provides instructions for producing the protein filamin A, which helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Certain mutations in the FLNA gene result in an impaired FLNA protein that cannot perform this function, disrupting the normal migration patterns of neurons during brain development.
Periventricular heterotopia is a rare condition. Its incidence is unknown.
Periventricular heterotopia can have different inheritance patterns. When this condition is caused by mutations in the FLNA gene, it is inherited in an X-linked dominant pattern.
Published Date: February 01, 2018Published By: National Institutes of Health