Agenesis of the Corpus Callosum

Introduction

The corpus callosum is the major interhemispheric bundle of commissural fibers in the brain that allows the transfer of motor, sensory, and cognitive information between the 2 hemispheres. Several abnormalities may affect the corpus callosum, including complete or partial agenesis, dysgenesis (an abnormal shape), or hypoplasia (decreased thickness).1 These malformations can occur in isolation; in association with chromosomal, syndromic, or monogenic disorders; or, rarely, secondary to infectious, ischemic, or teratogenic causes.

Summary

Complete and partial ACC are usually suspected when indirect signs are detected on routine axial scanning planes of the fetal brain. Not all signs have to be present simultaneously to suspect this diagnosis and to prompt detailed neuroimaging. Fetal neurosonography, by transvaginal ultrasonography if possible, should be performed to obtain the median and coronal planes. Fetal MRI and amniocentesis with CMA are important components in the prenatal workup. Prognostication in isolated ACC is difficult because of the variation in neurodevelopmental outcomes that cannot be predicted by neuroanatomic findings.