earliest known description of the disease was in 1841 by American physician Charles Oscar Waters. The condition was described in further detail in 1872 by American physician George Huntington. The genetic basis was discovered in 1993 by an international collaborative effort led by the Hereditary Disease Foundation. Research and support organizations began forming in the late 1960s to increase public awareness, provide support for individuals and their families and promote research. Research directions include determining the exact mechanism of the disease, improving animal models to aid with research, testing of medications and their delivery to treat symptoms or slow the progression of the disease, and studying procedures such as stem-cell therapy with the goal of replacing damaged or lost neurons. Signs and symptoms Signs and symptoms of Huntington's disease most commonly become noticeable between the ages of 30 and 50 years, but they can begin at any age, and present as a triad of motor, cognitive, and psychiatric symptoms. When developed in an early stage it is known as juvenile Huntington's disease. In 50% of cases, the psychiatric symptoms appear first. Their progression is often described in early stages, middle stages, and late stages with an earlier prodromal phase. In the early stages, subtle personality changes, problems in cognition, and physical skills, irritability, and mood swings occur, all of which may go unnoticed, and these usually precede the motor symptoms. Almost everyone with HD eventually exhibits similar physical symptoms, but the onset, progression, and extent of cognitive and behavioral symptoms vary significantly between individuals. The most characteristic initial physical symptoms are jerky, random, and uncontrollable movements called chorea. Many people are not aware of their involuntary movements, or impeded by them. Chorea may be initially exhibited as general restlessness, small unintentionally initiated or uncompleted motions, lack of coordination, or slowed saccadic eye movements. These minor motor abnormalities usually precede more obvious signs of motor dysfunction by at least three years. The clear appearance of symptoms such as rigidity, writhing motions, or abnormal posturing appear as the disorder progresses. These are signs that the system in the brain that is responsible for movement has been affected. Psychomotor functions become increasingly impaired, such that any action that requires muscle control is affected. When muscle control is affected such as rigidity or muscle contracture this is known as dystonia. Dystonia is a neurological hyperkinetic movement disorder that results in twisting or repetitive movements,