To the Editor: There have been numerous unsuccessful attempts to identify the carrier state for Huntington's disease in asymptomatic patients. A test that has attracted interest is based on the observation that levodopa can induce choreiform movements in patients with Parkinson's disease,1 and on the hypothesis that the neurons of patients with Huntington's disease are hypersensitive to dopamine.2 The administration of levodopa before the onset of the illness might produce choreic movements in carriers of the gene for Huntington's disease. Trials of levodopa in the early detection of Huntington's disease3 produced encouraging results in an eight-year follow-up study,4 although one. © 1982, Massachusetts Medical Society. All rights reserved.