Bilateral congenital oculomotor nerve palsy in a child with brain anomalies.

We treated a 3-month-old boy with bilateral congenital oculomotor nerve palsy in whom a magnetic resonance imaging scan demonstrated a developmental brain anomaly in the region of the basal ganglia. The pupil was normal on one side, and there was no aberrant regeneration of the oculomotor nerve. We could find no evidence for a peripheral oculomotor nerve lesion. This demonstrates that congenital oculomotor nerve palsy can be caused by brainstem disease. Embryologically, basal ganglia and oculomotor nuclei develop at the same time, and the Edinger-Westphal nucleus develops later. Thus, pupil sparing does not exclude a central origin for congenital oculomotor nerve palsy.