- Spinocerebellar ataxia type 6: gaze-evoked and vertical nystagmus, Purkinje cell degeneration, and variable age of onset. Gomez, C.M., Thompson, R.M., Gammack, J.T., Perlman, S.L., Dobyns, W.B., Truwit, C.L., Zee, D.S., Clark, H.B., Anderson, J.H. Ann. Neurol. (1997)