Ophthalmoplegia and dissociated nystagmus in adetalipoproteinemia

A characteristic pattern of acquired exotropia, progressive paresis of the medial rectus muscles, and dissociated nystagmus on lateral gaze was found in three patients with abetalipoproteinemia. Study with electronystagmography of the eye movements of one patient revealed abnormally slow voluntary saccades and slow or absent fast components of vestibular nystagmus, optokinetic nystagmus, and jerk-type, disassociated nystagmus. Defects in central nervous system centers generating saccadic eye movements are postulated.