Pendular nystagmus in hypomyelinating leukodystrophy.

We report the case of a 49-year old woman affected by hypomyelinating leukodystrophy. She presented with typical pendular nystagmus that was analyzed with video-oculography which is provided in the supplementary material of the report. The pendular nystagmus was accompanied by upper limb ataxia on the index-to-nose test. The video was partly recorded with a slow-motion technique in order to better demonstrate the ataxia and the pendular nystagmus. The brain MRI demonstrated a characteristic pattern of hypomyelination. Pendular nystagmus is a key clinical sign that contributes to the diagnosis of CNS hypomyelination when a leukodystrophic pattern is observed on brain MRI.