Objective: To review the embriology and clinical aspects of holoprosencephaly and agenesis of the corpus callosum.
Development: The rostral neuropore closes at 24 days of gestation. At 74 days of gestations axons cross through the dorsal region of the commissural plaque and start forming the corpus callosum. At 115 days of gestations the corpus callosum reaches its adult form. Holoprosencephaly occurs due to rostral mesodermal dysfunction. The etiology of holoprosencephaly is heterogenous. The risk of holoprosencephaly of neonates born to mother with gestational diabetes is 1 2 %. Agenesis of the corpus callosum not associated to holoprosencephaly is due to a disorder of telencephalic midline. Pyruvate dehydrogenase and non ketotic hyperglycinemia can produce agenesis corpus callosum. The prognosis of patients with agenesis of the corpus callosum is dictated by the associated central nervous system and none central nervous system anomalies.
Conclusions: Knowledge of the embriology of holoprosencephaly and agenesis of the corpus callosum are necessary to understand their radiological appearance. The evaluation of a neonate with these conditions requires genetic and metabolic evaluations.