Disrupted formation of the corpus callosum is the second most common central nervous system birth defect, occurring in approximately 1 in 3000 live births. The incidence of epilepsy in patients with agenesis of the corpus callosum (ACC) and its related syndromes ranges from 25% to 62%. Aicardi syndrome is a presumed X-linked syndrome, as it is seen only in females and Klinefelter syndrome (XXY) males. The ARX gene is a homeobox gene that has been shown to be crucial in forebrain, pancreatic, and testicular development. Andermann syndrome, also known as peripheral neuropathy associated with agenesis of the corpus callosum (ACCPN). An autosomal dominant disorder, Mowat-Wilson, is caused by de novo mutations or deletions within the ZFHX1B (ZEB2) gene. Recent work in studying large cohorts of ACC individuals is providing insight into the diversity of causes which lead to ACC, which will provide important insight into mechanisms and outcomes.

Polymicrogyria has been related to mutations of several genes including SRPX2, PAX6, TBR2, KIAA1279, RAB3GAP1, COL18A1 and copy-number variations. The spectrum of clinical manifestations associated with polymicrogyria ranges from normal individuals with only selective impairment of cognitive functions. Generalized polymicrogyria is often accompanied by microcephaly and severe-profound cognitive and motor delay, as well as epilepsy. Both polymicrogyria and schizencephaly have been reported in the same family and both may occur with prenatal cytomegalovirus infection. Clinical findings include focal seizures present in most patients usually beginning before age 3 years if bilateral clefts are present. Epilepsy, motor impairment, and disorders of higher cortical functions are the most common clinical manifestation of polymicrogyria. Specific electroclinical features of Aicardi syndrome include early onset infantile spasms and partial seizures. Electroencephalography in polymicrogyria and schizencephaly shows variable patterns of abnormality. Selected patients with schizencephaly have been treated with surgery for epilepsy.