Myoclonus, blepharospasm, ataxia, chorea, and other findings in juvenile Huntington disease

This young man has juvenile Huntington disease. Initially, he appears bright but displays blepharospasm, sometimes accompanied by facial grimacing, apraxia of eye opening, impersistence of tongue protrusion, generalized chorea, and slowing of rapid alternating movements associated with synkinetic movements of his fingers on the left, reflecting greater impairment; he has a normal gait. Three years later, he appears dull, with slackened jaws and masked face. Mental status testing indicated progressive dementia (not shown). He has markedly impaired rapid alternating movements. Generalized myoclonic jerks frequently occur spontaneously and can be induced by a sudden loud sound (stimulus-sensitive myoclonus). He has difficulty arising from his chair, turns en bloc, has absent arm swing, and has a slow, unsteady, broad-based gait associated with dystonic posturing of his wrists. (Contributed by Dr. Joseph Jankovic.)