Agenesis of the corpus callosum commonly occurs with which of the following disorders of brain formation?

• A. Dandy-Walker Syndrome
• B. Hydrocephalus
• C. Holoprosencephaly
• D. Spina bifida

Answer: (A)

Agenesis of the corpus callosum reflects a disruption in midline brain development that often signals broader midline malformations. Dandy-Walker malformation, characterized by cerebellar vermis hypoplasia or aplasia and fourth ventricle dilation with an enlarged posterior fossa, is a classic midline hindbrain anomaly. Because both ACC and Dandy-Walker arise from disturbances in midline patterning during the same early developmental window, they frequently occur together. This makes Dandy-Walker malformation the most likely associated brain formation disorder in this context. Other options involve different types of problems—hydrocephalus is a CSF-flow issue that can accompany many conditions, holoprosencephaly is a forebrain cleavage defect, and spina bifida is a spinal neural tube defect—so they’re less characteristically linked to ACC.