Neuronal intranuclear hyaline inclusion disease with progressive cerebellar ataxia.

Neuronal intranuclear hyaline inclusion disease is a progressive, fatal neurologic condition characterized by eosinophilic inclusions in neurons of the central, autonomic, and peripheral nervous systems. The clinical and pathologic findings of a 4-year-old boy who presented with a rapidly progressive cerebellar ataxia and seizure disorder that had begun 2 years earlier are described. Although intraneuronal inclusions were identified in neurons of cortex, basal ganglia, brainstem, cerebellum, and spinal cord, clinical signs were restricted to cerebellar ataxia, internuclear ophthalmoplegia, and cognitive delay. Predominant cerebellar atrophy, early age of onset, and short clinical course distinguishes it from previously reported patients.