Parkinson's disease is a progressive disease of the nervous system which affects around one person in every 500 in the UK. The disease becomes more common with increasing age. Symptoms usually first appear in people over the age of 50, although younger people can also develop the disease.
There is no evidence that Parkinson's disease is hereditary, although in around 5 per cent of cases there is another family member affected. It is believed that genetics may make some people more prone to developing Parkinson's disease but only if combined with exposure to external factors. To date, scientists have identified nine genes linked to Parkinson's disease.