A developmental defect in which either all or part of the corpus callosum fails to develop.
Agenesis can result from various etiologies, including genetic predisposition, chromosomal abnormalities, or intrauterine trauma, such as infection. When present, this condition is commonly associated with other neuroanatomical anomalies, metabolic disturbances, and/or neurobehavioral deficits. The latter might include mental retardation, seizures, motor deficits, and psychiatric disturbances. However, some patients may be relatively asymptomatic, the callosal defect being discovered only serendipitously late in life. The latter is more likely to occur when the agenesis is not accompanied by other neurological or metabolic defects. Whereas “disconnection syndromes” are routinely present following surgical commissurotomy for intractable epilepsy, they are generally not present with agenesis.