Cortical malformation and pediatric epilepsy : A molecular genetic approach

Genetic malformations of the cerebral cortex are important causes of neurologic morbidity in children because they are often associated with developmental delay, motor disturbances (cerebral palsy), and epilepsy. Primary autosomal recessive microcephaly is a cortical malformation with a low incidence of epilepsy. One of its causative genes, ASPM, might play an important role in regulating proliferation of neuronal progenitor cells. Mutations in ASPM do not seem to affect later stages of cortical development, such as neuronal migration, and this might be responsible for the low epileptogenicity of this malformation. ASPM might also have played an important role in the evolutionary expansion of the human brain. Bilateral frontoparietal polymicrogyria, on the other hand, is a highly epileptogenic malformation. Its causative gene, GPR56, is also expressed in the neurogenic regions of the cortex, but its primary function might be in the determination of cell fate and/or cortical patterning. Further studies of these genes will likely lead to a better understanding of human brain development and epilepsy.