Neurobiological Predictors of Huntington's Disease (PREDICT-HD)

People at risk for HD, who have been tested for the HD gene mutation, and who have not been diagnosed with symptoms of HD.

Inclusion Criteria:

• men and women at risk for HD, who have been tested for the HD gene mutation, and who have not been diagnosed with symptoms of HD (CAG ≥36 for CAG-expanded group or CAG <36 for CAG-norm group).

Exclusion Criteria:

• diagnosis of manifest HD (at least 50% confidence by neurologist that symptoms are present);
• clinical evidence of unstable medical or psychiatric illness;
• history of mental retardation;
• history of other CNS disease or event (e.g., seizures or head trauma);
• current or previous treatment with antipsychotic medications, including the traditional neuroleptics such as haloperidol as well as the atypical antipsychotics risperidone, clozapine, quetiapine, and olanzapine;
• treatment with phenothiazine-derivative antiemetic medications such as prochlorperazine, metoclopramide, promethazine, and Inapsine on a regular basis (greater than 3 times per month);
• pacemaker or metallic implants.