Huntington’s Disease (HD)

Abstract

In 1872, George Huntington, a Long Island physician, drew on his own experience and that of his father and grandfather to provide a graphic description of the inherited neurodegenerative disease that now bears his name. Originally known as Huntington’s chorea, the disorder is characterized by progressive involuntary choreiform (dancelike) movements, psychological change, and dementia. It is caused by a dominant gene of as yet unknown function. The onset of symptoms can occur at any time in life but most commonly begins in the fourth to fifth decade. In a small percentage of cases which have been termed juvenile onset HD, the first symptoms occur before age 10. The initial signs of motor disturbance are slight, involving such features as awkwardness of gait, clumsiness, facial twitching, or subtle involuntary movement of the fingers. As the disorder progresses the involuntary movements become more frequent, pronounced, and exaggerated, impairing and eventually eliminating normal day-to-day activity by interfering with the ability to walk, stand, write, speak, and swallow. In some cases, especially those with juvenile onset of symptoms, extreme rigidity is seen rather than chorea. Emotional and behavioral changes often accompany or precede the onset of movement disorder and can similarly have a profound impact on ability to function and on interaction with family members. Impulsive, erratic behavior, impaired memory, poor concentration, and moodiness can all be early signs of HD. In particular, chronic depression occasionally precedes motor symptoms by many years. There is currently no effective treatment for halting or even delaying the progression of HD. Some 15 to 20 years after initial onset of symptoms, the HD victim usually dies of heart disease, pneumonia secondary to aspiration, or choking.