George Huntington was not a prolific researcher. In fact, he only published three scientific papers in his career. The first of these, however, published in 1872 when Huntington was just 22 years old, would lead to his name being found in most neuroscience textbooks today.

In that paper, titled On chorea, Huntington discussed a disorder called chorea that had been known since the Middle Ages. The word chorea comes from the Geek word choreia, which means to dance, and it was used to describe a disorder characterized by involuntary, spasmodic movements of the limbs that bore some resemblance to an odd dance.

There are a number of different types of chorea, each linked to a different underlying cause. George Huntington wrote the best description to that point of a particular form of chorea that began in adulthood and was inherited, inexorably progressive, and always fatal. Within a few decades, the chorea Huntington described was widely-recognized as a unique disorder, which---in appreciation for Huntington's clear and accurate depiction of the disease---was called Huntington's chorea. The name was eventually changed to Huntington's disease (HD), as it became apparent that the condition involved more than just chorea. Not all patients with HD develop chorea and even those who do experience a number of other symptoms that are not related to movement.

In the 20th century, the hereditary nature of HD became even clearer as our understanding of common patterns of inheritance improved. In the 1980s, a gene was identified that seemed to be the cause of HD. With this discovery, HD joined a short list of diseases caused by the mutation of a single gene.

What is Huntington's disease?

The symptoms of HD can appear at any age, but typically emerge in middle age (the average age of onset is 40 years). At first, patients will often experience subtle changes in personality, cognition, and movement. For example, a patient might become irritable, have trouble remembering things, or be especially restless or fidgety. These symptoms, however, are usually not enough to lead to a diagnosis.

The early symptoms then progress into symptoms that allow for a clear diagnosis of HD. These include: conspicuous movement problems like chorea, impaired coordination and balance, abnormal eye movements, and muscle rigidity. Also, cognitive symptoms can become debilitating, and can involve difficulty focusing, a tendency to become fixated on a thought, lack of impulse control, and lack of awareness. Psychiatric symptoms like depression, insomnia, and fatigue are common as well.