FAMILIAL TREMULOUS AND MYOCLONIC DYSTONIA WITH WHITE-MATTER CHANGES IN BRAIN MAGNETIC-RESONANCE-IMAGING

We report two families with a disorder, probably autosomal recessive, characterized by tremor of juvenile onset, dystonia, and myoclonus wit h preserved cognitive, cerebellar, and peripheral nervous system funct ions. During 4 years' follow-up, mild spasticity appeared. Magnetic re sonance imaging (MRI) revealed mild diffuse changes in the white matte r. Central conduction times for visual, motor, and sensory systems wer e all prolonged. Extensive metabolic work-up failed to reveal lysosoma l, peroxisomal, mitochondrial, or other metabolic abnormalities.