Pendular nystagmus in patients with peroxisomal assembly disorder.

BACKGROUND Pendular nystagmus commonly occurs in congenital and acquired disorders of myelin. OBJECTIVE To characterize the nystagmus in 3 siblings with an infantile form of an autosomal recessive peroxisomal assembly disorder causing leukodystrophy. DESIGN We examined visual function and measured eye movements using infrared oculography. We noted changes in eye speed and frequency before and after the administration of gabapentin to 1 patient. RESULTS All 3 siblings showed optic atrophy and pendular nystagmus that was predominantly horizontal, at a frequency of 3 to 6 Hz, with phase shifts of 45 degrees to 80 degrees between the oscillations of each eye. Gabapentin administered to 1 child caused a modest improvement of vision and the reduction of the velocity and frequency of oscillations in the eye with worse nystagmus. CONCLUSION The pendular nystagmus in these patients was due to their leukodystrophy and may have a similar pathogenesis to the oscillations seen in other disorders affecting central myelin.