According to the Huntington's Disease Association, ‘‘Huntington's disease, which is often called HD, is an hereditary disorder of the central nervous system. It used to be known as Huntington's Chorea or HC. Huntington's disease usually develops in adulthood and can cause a very wide range of symptoms. The disease affects both men and women.
Huntington's disease is caused by a faulty gene on chromosome 4. The gene, which produces a protein called Huntingtin, was discovered in 1993. In some way - which is not yet understood - the faulty gene leads to a damage of the nerve cells in areas of the brain, including the basal ganglia and cerebral cortex. This leads to gradual physical, mental and emotional changes.
Each person whose parent has Huntington's disease is born with a 50-50 chance of inheriting the faulty gene. Anyone who inherits the faulty gene will, at some stage, develop the disease. A genetic test is available from Regional Genetic Clinics throughout the country. This test will usually be able to show whether someone has inherited the faulty gene, but it will not indicate the age at which they will develop the disease.’’
It has been known that HD is an hereditary disease since the 1800s. It seems that sufferers of HD produce a faulty version of the Huntingtin protein that may interfere with nerve cell function. In European countries between 1.63 – 9.95 per 100,000 people (Revilla and Grutzendler 2004) have HD.