Gray matter heterotopia

What it means

Heterotopia or neuronal heterotopia are macroscopic clusters of misplaced neurons (gray matter), most often situated along the ventricular walls or within the subcortical white matter.

Gray matter heterotopia is caused by clumps of gray matter being located in the wrong part of the brain. It is characterized as a type of cortical malformation. The neurons in heterotopia may appear to be normal, except for their mislocation; nuclear studies have shown glucose metabolism equal to that of normally positioned gray matter. The condition causes a variety of symptoms, but usually includes some degree of epilepsy or recurring seizures, and often affects the brain's ability to function on higher levels. Symptoms range from nonexistent to profound, in which case heterotopia can result in severe seizure disorder, loss of motor skills, and mental retardation. Neuronal heterotopia consists of gray matter within the white matter, and the term gray matter heterotopia is more frequently used.

Rare diseases that can present with this21

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Gray matter heterotopias · Grey matter heterotopia · Grey matter heterotopias · Heterotopia · Heterotopias · Neuronal heterotopia