An unusual cause of head drops.

The presence of vertical ocular motor apraxia should prompt a careful assessment to detect an underlying neurometabolic condition. But congenital vertical ocular motor apraxia is a rare entity that may be attributed to perinatal stroke, hypoxia or kernicterus. We report a case of a 5-year old girl with congenital vertical ocular motor apraxia. Her magnetic resonance imaging (MRI) brain showed symmetrical high signal in the inferomedial thalamic nuclei in the distribution of the vessel of Percheron, a rare posterior cerebral artery variant. Awareness of this rare cause of childhood stroke may obviate unnecessary investigation.