Early cognitive and motor symptoms in identified carriers of the gene for Huntington disease

Objective: To study early motor and cognitive symptoms in Huntington disease. Design: A follow-up cohort study after a DNA test pro cedure in which gene carriers and noncarriers were identified among people genetically at risk for Huntington disease. Setting: Leiden University Medical Center, Department of Neurology, Leiden, the Netherlands, in cooperation with the Clinical Genetics Center Leiden and the Department of Medical Psychology and Psychotherapy, Erasmus University Rotterdam, Rotterdam, the Netherlands. Participants: Thirty-three individuals: 9 unaffected gene carriers, 6 gene carriers with motor symptoms, and 18 noncarriers of the gene for Huntington disease. Main Outcome Measures: A neuropsychologic examination covering a broad area of cognitive functioning, reaction time procedures, and motor tasks. Results: The neuropsychologic assessment showed no significant differences between presymptomatic gene carriers and noncarriers. Three motor tasks differentiated between these 2 groups on a liberal .05 P level (analysis of variance followed by the Student t test). The affected gene carriers performed less well than the presymptomatic gene carriers acid the noncarriers in 10 motor tasks and 7 cognitive tasks. These differences were significant at P<.05. Conclusion: Motor symptoms play a more prominent and unequivocal role than cognitive symptoms in early stages of Huntington disease.