Congenital and acquired abnormalities of the pediatric brain

The normal development of the brain is highly complex and involves multiple, tightly linked, interacting, and well-defined genetically programmed processes. Any interference with the normal development may have a significant impact on quality of life. Typically, developmental abnormalities of the brain are classified as congenital versus acquired. This classification may seem straightforward: for example, a rhombencephalosynapsis (congenital fusion of cerebellar hemispheres) is a classic congenital malformation, whereas an intrauterine focal thromboembolic cerebral infarction is a typical acquired lesion. There is, however, a significant overlap. Focal hypoperfusion of a part of the developing brain may interfere with normal neuronal migration, resulting in a migrational abnormality or even in more severe brain abnormalities. In this situation, an acute event has interfered with normal development, resulting in a developmental disorder of the brain. In congenital abnormalities, the malformation may result from a genetically encoded aberrant brain development.