It is usually characterised by involuntary movement and intellectual, emotional and behavioural problems.
In most cases HD is a "late" onset disease and symptoms generally appear when a person reaches their mid thirties or forties. In rare cases HD may develop in childhood or as late as seventy years of age.
Treatment of HD and research into its causes has greatly improved in recent years. The HD gene was isolated in 1993 but there is still no cure for the disease.