Definition of Chorea including Huntington's Chorea and Corea
Chorea means dance In Greek, and the word refers to the involuntary wringing and rolling movements that characterize the disease group. The disease arises deep in an area of the brain, called the basal ganglia. Here the balance between the substances is compromised (see below Parkinson's disease, which also causes this imbalance), depriving the patient of normal muscle control resulting in involuntary, irregular and rapid movements affecting limps, the face and other body parts.
Chorea is absent during sleep.
Classification and causes
The term Sydenham's Chorea was previously used for all forms of Chorea. Today the term covers only Chorea minor, which is a rare disease sometimes seen in children after an infection with streptococci.
The most common form of Chorea is Huntington's Chorea with an incidence of 3 in 100,000. The disease is hereditary with a 50% probability.
It might also occur in connection with pregnancy where it is termed Chorea Gravidarum.
DNA tests can pinpoint the gene responsible for the disease and thus indicate a family risk of the disease and allowing potential patients precautionary steps for example in connection with pregnancy.
Symptoms and treatment
In Huntington's Chorea symptoms typically begin to show up when patients are in their forties primarily as involuntary and excessive movements and dementia. Treatment does not change the condition, but can mitigate the symptoms.
Outlook
The disease duration is usually 10-15 years ending fatally.
Chorea minor also results in involuntary movements and psychiatric symptoms but these usually disappear over time. However, there may be relapses over a longer periode. | 
