Genetic defects of human brain development.

This review focuses on malformations of the central nervous system that have a genetic etiology. One can view each malformation as giving us unique details on a map entitled "how to make a human brain." The gene(s) that cause each malformation are being identified, allowing discovery of their specific role in neurodevelopment, and defining a "road" on the map. The malformation is then the developmental consequence of "taking a wrong turn." Assimilation of complementary data from other species with human malformation phenotype and genotype is revealing just how wonderful and complex the neurodevelopment map is. Here we highlight recent research on brain malformations and how this is illuminating the map of normal human brain formation.