Abstract
Introduction
Neuropsychiatric symptoms that are atypical in severity or pattern for an established diagnosis may warrant further evaluation for an underlying neurologic etiology. In this case, a patient who had been diagnosed with both attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) was found to have complete congenital agenesis of the corpus callosum (AgCC), which may contribute to his constellation of emotional, behavioral, and memory symptoms. AgCC may occur as an isolated malformation or in association with other congenital abnormalities and genetic syndromes, with prognosis influenced substantially by the presence of additional malformations.
Case Info
This patient is a 21-year-old male with a past medical history of ADHD and ASD who was referred to neurology for evaluation of chronic memory impairment. He reported poor memory and concentration beginning in second grade, with persistent effects on his daily functioning. He received a Montreal Cognitive Assessment (MoCA) score of 21/30 and a memory index score of 12/15 at his neurology intake appointment. Neuropsychological testing demonstrated memory deficits substantially greater than typically expected with ADHD, which the evaluating neuropsychologist described as resembling a pattern seen in dementia. The patient subsequently underwent MRI of the brain without contrast, which revealed a complete absence of the corpus callosum with colpocephaly. Additional findings included subependymal gray matter heterotopia along the right temporal horn. The posterior horns of the lateral ventricles were symmetrically dilated, with mild displacement of the third ventricle.
The patient continues to undergo psychotherapy and supportive counseling, and he takes bupropion and methylphenidate daily. He has not undergone further workup at this time.
Disc Clinical
Further evaluation may help determine whether AgCC is isolated or associated with a broader genetic or congenital syndrome. The presence of additional CNS abnormalities can increase suspicion for an underlying syndromic or genetic etiology. In this patient, gray matter heterotopia represents an additional CNS malformation warranting consideration of further evaluation. A comprehensive assessment may include a three-generation family history, detailed developmental and physical examination, evaluation for associated abnormalities, and genetic testing such as chromosomal microarray.
Given the additional CNS abnormality identified on MRI, further clinical and genetic evaluation may help determine whether the patient's AgCC represents an isolated malformation or part of a broader congenital syndrome.
Conclusion
Agenesis of the corpus callosum is a congenital malformation with a highly variable clinical presentation. When identified on imaging, careful evaluation for associated CNS abnormalities and other congenital or genetic findings can help distinguish isolated AgCC from a broader syndromic process and guide appropriate management.