Oculomotor abnormalities in chronic GM2 gangliosidosis

The clinical and electro-oculographic eye abnormalities in chronic GM2 gangliosidosis have been described. The most prominent oculomotor disturbances in our patients involved the pursuit system. This was evident during performance of eye tracking and vestibulo-ocular reflex suppression. Saccadic eye movements were dysmetric but were normal in velocity. These findings point to disturbances of cerebellar oculomotor control. While the oculomotor defects are nonspecific in this chronic form of beta-hexosaminidase A deficiency, they broaden the spectrum of clinical features considered to be typical ocular manifestations in many storage diseases. Disturbances in the oculomotor system may be the only ocular sign of chronic GM2 gangliosidosis.