Menzel's hereditary ataxia with slow eye movements and myoclonus. A clinico-pathological study

The patient we describe had cerebellar ataxia, slow eye movements, myoclonus, facial dystonia and signs of spinal cord and peripheral nerve involvement. The patient's mother, brother and sister died from the same disease. Neuropathological examination revealed lesions of olivo-ponto-cerebellar atrophy (OPCA) associated with spinal cord degenerative changes characteristic of Menzel's hereditary ataxia. Although myoclonus was similar to Hunt's dyssynergia cerebellaris myonica, pathological findings did not show significant involvement of the dentate nucleus or superior cerebellar peduncle and physiopathological hypotheses for myoclonus are discussed. Slow eye movement is emphasized in the propositus and we suggest that it could be specific of one type of OPCA. Its pathological significance is discussed, but a primitive and unique involvement of the paramedian pontine reticular formation is unlikely.