Dandy-Walker Malformation and Optic Nerve Hypoplasia: A Developmental Case Highlighting the Psychiatric Impact of Central Nervous System Malformation.

Dandy-Walker malformation (DWM) and optic nerve hypoplasia (ONH) are rare congenital anomalies associated with neuropsychiatric morbidity, but their co-occurrence in adults has not been described. We present an adult patient with both DWM and unilateral ONH who developed auditory hypersensitivity, visual agnosia, phonological dyslexia, dysgraphia, and longstanding academic challenges, later evolving into recurrent depression, anxiety, and insomnia. Neuroimaging revealed a Dandy-Walker variant with cerebellar atrophy and ONH, and her presentation was consistent with cerebellar cognitive affective syndrome. Notably, despite the established risk of autism spectrum-like traits in both DWM and ONH, she did not demonstrate autistic features. This case highlights how overlapping congenital anomalies may synergistically increase vulnerability to psychiatric illness and underscores the importance of early recognition and tailored interventions. To our knowledge, this is among the first adult cases describing co-occurring DWM and ONH with a longitudinal psychiatric course.