What causes Bilateral perisylvian polymicrogyria ?
What causes bilateral perisylvian polymicrogyria? The exact underlying cause of bilateral perisylvian polymicrogyria (BPP) is unknown. The signs and symptoms associated with the condition are thought to be due to improper development of the outer surface of the brain (cerebral cortex) during embryonic growth. The cerebral cortex, which is responsible for conscious movement and thought, normally consists of several deep folds (gyri) and grooves (sulci). However, in people affected by BPP, the cerebral cortex has an abnormally increased number of gyri that are unusually small. Scientists believe that these abnormalities occur when newly developed brain cells fail to migrate to their destined locations in the outer portion of the brain. Specific non-genetic causes of polymicrogyria have been recognized, including exposure to cytomegalovirus infection (CMV) during pregnancy. Polymicrogyria has also been associated with certain complications in twin pregnancies.