In the human brain there are a number of spaces known as ventricles. Individuals with periventricular heterotopia have misplaced nodules of neurons along the lateral ventricles which can be seen using magnetic resonance imaging (MRI). Patients, who are generally of normal intelligence, present with epilepsy and sometimes dyselxia.
Periventricular heterotopia can be caused by genetic mutations, infection, injury or radiation. Two genes are known to cause the disorder: Filamin A and ARFGEF2.