PREVIOUS descriptions of Alexander's disease have generally been of cases in young children.1-8The clinical picture most often associated with this disease has been one of developmental retardation and enlargement of the head. Vogel and Hallervorden,9however, described a case in a 15-year-old girl that began with weakness of the left leg and foot at age 7 and progressed to spasticity and contractures of the lower extremities, eventual weakness of the upper extremities, and development of blurred vision, nystagmus, dysarthria, and dysphagia. The brain was atrophic, weighing 990 gm at autopsy. Stevenson,10referring to this case, stated that the patient "presented the picture that one would think might be multiple sclerosis." Rewcastle11presented a case of a 26-year-old man whose symptoms began at age 14 with weakness of the legs, followed by arm weakness, incontinence, diplopia, and difficulty with speech and swallowing. Findings on examination included