3 learning resources available for this topic
Agenesis of corpus callosum (ACC) is a congenital brain malformation characterized by the partial or complete absence of the corpus callosum, the major white matter tract connecting the cerebral hemispheres. This condition affects interhemispheric communication and can range from isolated findings to complex syndromes with associated anomalies.
ACC results from developmental failure during embryogenesis between 10-20 weeks of gestation when the corpus callosum normally forms through axonal growth across the interhemispheric fissure. The absence of normal callosal fibers leads to compensatory neuronal pathways through anterior and posterior commissures, though these cannot fully replace normal interhemispheric communication.
Diagnosis is typically made through neuroimaging showing absent or incomplete corpus callosum with characteristic findings like colpocephaly (enlarged posterior horns) and high-riding third ventricle. Clinical presentation varies widely from asymptomatic individuals to those with intellectual disability, seizures, or associated malformations, requiring comprehensive evaluation to distinguish isolated ACC from syndromic forms.