What is agenesis of the corpus callosum?

What is agenesis of the corpus callosum?

Agenesis of the corpus callosum (ACC) is a birth defect that affects the brain. A person with ACC has a missing or partially missing corpus callosum. The corpus callosum is a thick bundle of nerve fibers that connects the right and left hemispheres (halves) of the brain. It allows both sides of the brain to communicate with each other.