The cerebral hemispheres can be large, small or asymmetric; the gyri may be missing be great exceedingly numerous or small.
In addition to the gross visible deformation microscopic sections of normal appearing brain can show a disorganization of the normal, laminar, neural structure. Localized deposits of gray matter in areas where usually only white matter occurs, may be present (heterotopic gray matter).
The cerebral hemispheres can be large, small or asymmetric; the gyri may be missing be great exceedingly numerous or small. In addition to the gross visible deformation microscopic sections of normal appearing brain can show a disorganization of the normal, laminar, neural structure. Localized deposits of gray matter in areas where usually only white matter occurs, may be present (heterotopic gray matter). Malformations of the brain hemispheres may have genetic or acquired causes. Among the acquired causes include infections (eg. As cytomegalovirus) and vascular events that disrupt the blood supply to the developing brain. Microcephaly or macrocephaly, a moderate to severe motor and mental retardation and epilepsy are common in these malformations. Treatment is supportive, including anticonvulsants, if needed. Holoprosencephaly A holoprosencephaly occurs when the embryonic forebrain is not divided into segments and columns. The front mid-brain, the skull and face are malformed. The abnormalities can be caused by defects produced by the Sonic hedgehog gene of the protein. The fetuses severely affected may die before birth. Treatment is supportive. Lissencephaly The lissencephaly consists of a very thick cortex, decreased or absent Gyrusmustern on the surface of the brain, reduced or abnormal lamination of the cerebral cortex and often diffuse neuronal heterotopia. This anomaly is caused by a pathological neural migration, a process in which the immature neurons are bound to their glial processes and migrate from its original position close to the ventricle to the surface of the brain. Several individual gene defects can cause this malformation (z. B. LIS1). The affected infants may have mental retardation and seizures (often infantile Spasmen- Infantile spasms). Treatment is supportive; survival depends on the severity of the seizures and the presence of other complications, including swallowing disorders, apnea and difficulties in clarifying oropharyngeal secretions. Polymicrogyria The polymicrogyria where the gyri are small and plentiful, also includes an abnormal neuronal migration. Other common findings include pellucidum a simplified or missing cortical lamination in affected regions, heterotopic gray matter, hypoplastic or absent corpus callosum and septum and malformations of the brainstem and / or cerebellum. The structural abnormalities can be diffuse or focal. The most common area of ??focal involvement is the perisylvian fissure (bilateral or unilateral). Polymicrogyria is strong with Schizencephaly (Porencephaly: Schizencephaly) associated, are present in the abnormal slots or gaps in the cerebral hemispheres. Numerous causes of polymicrogyria have been identified, including a number of single-gene mutations (eg. As of SRPX2) and primary maternal infection with cytomegalovirus (d. E. When the mother no prior immunity HAT congenital and perinatal cytomegalovirus (CMV)). The most common clinical manifestations include seizures, mental retardation and spastic hemiplegia or diplegia. Treatment is supportive.