Isolated Agenesis of the Corpus Callosum in a Four-Year-Old: A Case of Preserved Cognitive Function Despite Complete Corpus Callosum Absence

Agenesis of the corpus callosum (AgCC) is a rare congenital brain anomaly characterized by the partial or complete absence of the corpus callosum, a crucial structure responsible for interhemispheric communication. Neurological outcomes associated with AgCC vary widely, with presentation ranging from severe intellectual disabilities to normal cognitive function. The condition is often discovered incidentally due to the variability in its clinical presentation. This report discusses the case of a four-year-old Saudi boy with incidental AgCC identified following a minor head trauma. The patient was born full-term through spontaneous vaginal delivery without perinatal complications. He presented with a history of mild head trauma leading to recurrent, non-progressive headaches localized in the occipital region. Despite the head trauma, there were no signs of increased intracranial pressure or other neurological deficits. A neurological examination revealed a head circumference above the 95^th percentile, but all other parameters, including cranial nerve function, motor strength, and reflexes, were within normal limits. Neuroimaging through computed tomography and magnetic resonance imaging unexpectedly revealed complete agenesis of the corpus callosum. Despite this structural anomaly, the patient's cognitive function, assessed by the Mini-Mental State Examination and an IQ test, was within normal limits. The patient was managed conservatively for his head trauma and discharged with a recommendation for annual neurocognitive follow-up. This case highlights the variable presentation of AgCC, where, despite the complete absence of the corpus callosum, the patient demonstrated no significant neurocognitive deficits. The findings align with existing literature suggesting that isolated AgCC can present with a broad spectrum of cognitive outcomes, from profound intellectual disability to near-normal function. The case underscores the importance of ongoing neuropsychological monitoring in individuals with AgCC, particularly as cognitive demands increase with age. Additionally, this case emphasizes the need for increased awareness and education among clinicians regarding the potential for late-emerging neurocognitive challenges in patients with AgCC.