Juvenile Parkinson's disease and its response to L-dopa therapy

Four youngsters, between the ages of 13-27 years, presented dystonic foot. Two to three years following the appearance of the dystonic foot, cogwheel rigidity and tremor appeared on the dystonic foot side. Treatment with low doses of levodopa/carbidopa consistently reversed the symptoms. "On-off" phenomena appeared in the first years of treatment and persisted for the entire period of 5 to 15 years of illness. No parkinsonian signs were present when the dystonic foot appeared. Based on our observations and on a review of the literature, we conclude that responsiveness to low doses of L-dopa is the major marker of juvenile Parkinson's disease.