Although the relationship between Cplx1 and ataxia is not known [2] and [11], the high levels of Cplx1 expression in the cerebellum and thalamus [14], the reduced volume of these regions in Cplx1−/− mice reported here and the involvement of the cerebellum and thalamus in movement control seem to indicate that both these regions might be involved in the development of the abnormal motor function that is a result of Cplx1 depletion in mice. Here, CPLX1 is linked to cerebellar ataxia.