Onset of multiple sclerosis in a 24-month-old child.

A child, aged 24 months, incurred an episode of ataxic gait. Two months later, she had a recurrent episode of ataxic gait and bilateral blindness. Her symptoms were resolved with steroid therapy. A permanent visual deficit of 20/200 remained in the right eye. When she reached 16 years 10 months of age, she incurred the second episode of bilateral blindness. One month later, she had grand mal seizures. Her myelin basic protein level was elevated. Visual evoked responses were abnormal bilaterally. The combination of cerebellar, cortical, and eye symptoms, with a history of well-defined remissions, allowed the diagnosis of multiple sclerosis (MS) to be made. This is the youngest known patient with MS yet described, with the first attack occurring at 24 months of age.