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 opticatrophy and pendular nystagmus that was predominantly horizontal, at a frequency of 3 to 6 Hz, with phase shifts of 45°to 80°between the oscillations of each eye. Gabapentin administered to I 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.