PARKINSON'S disease afflicts tens of thousands of people in the UK. It is no respecter of age, and at present, there is no cure. It has had its share of celebrity sufferers; former boxer Muhammad Ali is a sufferer and Canadian actor Michael J Fox has just published a personal account of living with the disease.

As many as 120,000 people in the UK have the debilitating condition - one in 500 of the general population. This increases to one person in 100 over the age of 65 and one in 50 over the age of 80.

Greg Vines of the Parkinson's Disease Society says it is important to highlight awareness of the condition. ''Parkinson's can affect absolutely anybody. No one knows what causes it. It could be a mixture of environmental and genetic factors. Muhammad Ali was hit in the head a number of times as a boxer, but a lot of boxers don't get the disease, so he may have a predisposition for it.''

Parkinson's is a disease of the central nervous system which causes a loss of muscular co-ordination and involuntary shaking of the limbs. It is a progressive condition.

Vines explains: ''People lose the chemical called dopamine in their brain which enables them to perform smooth movements. Once they lose 80 per cent, it starts to affect movements they have performed since they were a baby, like walking, swallowing and talking. Like a car running out of oil, the brain will keep going because it has enough petrol but when the oil stops, nothing moves properly.''

Parkinson's affects sufferers differently but the three main symptoms are shaking, muscle stiffness and slowness of movement. Other symptoms can include a lack of facial expression, difficulties with speech and writing, tiredness and depression. Vines says: ''Parkinson's usually feels like it comes out of the blue but for two or three years you may feel something is not quite right.''

As it is identified as a condition that affects the elderly, younger sufferers have often found it difficult to get an accurate diagnosis. Actor Michael J Fox was just 30 when he was diagnosed - the first symptom was a twitch in one of his fingers. He waited seven years, until 1998, to announce his condition to the world and has now written a book about the experience, Lucky Man: A Memoir.

He has set up the Michael J Fox Foundation which is dedicated to finding a cure for Parkinson's by 2010. More information is available on www.michaelj fox.com

Approximately 10,000 people are diagnosed with the condition each year in the UK. Most people are over the age of 60, but one in 20 is under the age of 40 when first diagnosed, and one in seven is under the age of 50. Some studies have suggested that men are twice as likely to develop it as women, but it is not known why that is.

Drugs are the main treatment. They work to restore the level of dopamine in the brain. There can be some side effects such as hallucination and confusion, but there is no doubt that generally speaking it helps sufferers get on with their lives. Vines says: ''Drug treatment helps and people can get on with a normal life for many years. Some people have gone on for 30 or 40 years, but eventually it will get worse.''

Physical therapy such as physiotherapy and speech therapy are used and there are also surgical techniques, including brain implants. There have been some setbacks in recent surgical trials but it is hoped that gene therapy will eventually provide a breakthrough.

It is important to be patient with sufferers, says Vines. ''Give people time as communication problems can be very embarrassing. Symptoms include a fixed expression and freezing-up. For example, people may go out and not be able to hold a glass or smile. It is difficult to understand the condition. In the past people have been taunted because they look like they are drunk or bored. There has to be more understanding.''

* The Parkinson's Disease Society at www.parkinsons.org.uk is a national charity with 27,000 members and 270 branches nationwide set up to provide support for sufferers and their families alike. The National Parkinson's Freephone Helpline on 0808 800 0303 is open from Monday to Friday from 9.30am to 5.30pm.