Familial cerebellar degeneration with slow eye-movements, mental deterioration and incidental nevus of ota (oculo-dermal melanocytosis).

Four members of a family with an autosomal dominant form of cerebellar degeneration all had slow eye-movements, i.e. slow pursuit with absence of both nystagmus and rapid saccadic movements. Three showed progressive mental deterioration. One patient had nevus of Ota (oculodermal melanocytosis) and a history of grand mal epilepsy. In these four patients the symptoms first occurred between the ages of 10 and 31 years--the onset apparently appearing earlier with successive generations. Current studies implicate a brain-stem lesion of the paramedian pontine reticular formation in the pathogenesis of the oculomotor abnormality. The possibility of a neurocutaneous syndrome, specifically a 'melanophakomatosis', in the patient with seizures and nevus of Ota is discussed; however, absence of these findings in other affected relatives makes a fortuitous association more probable. The literature on nevus of Ota associated with neurological disease is considered.