Myelinated retinal fibers in autosomal recessive spastic ataxia of Charlevoix-Saguenay

Background: Myelinated retinal nerve fibers are considered a hallmark of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) in French Canadian patients. The demonstration of a worldwide distribution of this disease, as well as the almost invariable presence of a normal retina on fundoscopy in cases outside Canada, suggests that more quantitative methodologies are needed to assess the retina in ARSACS. Methods: To characterize better the retinal features of ARSACS, we studied five Italian patients by means of optical coherence tomography (OCT), a processing method that allows the creation of three-dimensional images with micrometer resolution. We compared OCT characteristics in ARSACS with those obtained from five subjects with persistent myelination of the retina, a rare congenital non-progressive anomaly. Results: Four patients with ARSACS showed myelinated retinal nerve fibers on ophthalmoscopy, corresponding to an increased thickness of the retina on OCT, a characteristic not present in the subjects with persistent myelination of the retina. Conclusions: Myelinated retinal fibers are not rare in Italian patients with ARSACS. This finding may be the consequence of the thickening of the retina, as detected by OCT.