Use of L-Dopa in the Detection of Presymptomatic Huntington's Chorea

Abstract

There is evidence that choreiform movements are related to an action of dopamine within the brain. In an attempt to identify subjects in whom Huntington's chorea will develop, L-dopa was given to 28 subjects genetically at risk for this disease. Similar regimens of L-dopa or L-dopa in conjunction with a dopa decarboxylase inhibitor were given to 24 control subjects. Of the 28 subjects at risk, chorea developed in 10 (35.7 percent) while they were receiving L-dopa. The chorea always disappeared on discontinuation of the L-dopa. None of 24 control subjects manifested chorea. It is suggested that patients in whom signs of chorea appeared during this procedure will later have Huntington's chorea. The failure of L-dopa to elicit abnormal movements in the controls suggests that there would be few false-positive results among the subjects at risk for Huntington's chorea. The failure to manifest chorea is less important, and in subjects in this group chorea may still develop.