Huntington's Disease (HD) is an inherited disease that causes changes in a person's ability to control movements, thinking, and feelings. The intent of this study is to learn more about the beginning changes in thinking skills, emotional regulation, and brain structure and function as a person begins the transition from health to HD.

Preliminary studies indicate that people with HD may have marked decline before an actual diagnosis. This study will help reveal the earliest indicators of the disease and what factors influence the age at which a person carrying the gene develops the disease. It is necessary to get information on the early stages of HD in order to develop drugs that can slow or postpone the onset of HD. The investigators hope this study will provide essential information for future trials of experimental drugs for HD.