Someone I'm close to has huntington's disease. What are the major signs or symptoms I should look out for?

Movement & Behavior. The major symptoms are changes in behavior such as hallucinations, irritability, moodiness and psychosis, and abnormal movements including extra facial and limb movements and loss of coordination, dementia, and eventually impairments of speech and swallowing. More information is available from the huntington's disease society of america: www.Hdsa.Org.