Experts believe it is caused by a loss of brain cells that produce a chemical messenger called dopamine.
Symptoms tend to worsen the longer a person has the disease because it is a progressive neurological disorder.
It differs from case to case but often includes a tremor or fine shake while the person is at rest, as well as rigidity of muscles, slowness of movement and unsteady balance.
Symptoms of Parkinson's disease include:
• Tremor (shaking)
• Slowness of movement
• Rigidity (stiffness)
• Physical and other symptoms of Parkinson's
• Bladder and bowel problems
• Eye problems
• Falls and dizziness
• Restless legs syndrome
• Skin, scalp and sweating problems
• Sleep problems
• Speech and communication problems
• Swallowing problems
• Hallucinations and delusions
• Memory problems
"Men are one-and-a-half times more likely to get Parkinson’s disease than women."
According to Parkinson's UK, it can make everyday tasks like getting dressed or using a computer and phone difficult and "frustrating".
"On top of symptoms affecting movement, people with Parkinson’s often experience problems such as tiredness, pain, depression and constipation, which impact their day-to-day lives," reads their site.
Symptoms can be controlled using a combination of drugs, therapies and occasionally surgery, but often more care and support may be needed as they progress.
Steve Ford, chief executive at Parkinson's UK, said diagnosis can be a "positive" experience for people.
He said: "Often people when they are diagnosed with Parkinson's will say 'Now I realise I've probably had it for several years'. They might have been living with a tremor in their fingers or a stiffness which is why diagnosis can be a positive and they can start treatment for a tremor or slowness of movement.
"It is important to say that the treatment can deal with some of the symptoms but not the underlying causes and Parkinson's is a progressive illness so as you go on more of the cells in the brain die and it gets worse although the rate at which it gets worse differs in individuals."
Ford said patients can also be helped with physiotherapy sessions, as well as speech and language therapy to help them deal with the symptoms.
The NHS also advises that: "Due to the advancements in treatment, people with Parkinson’s disease now often have a normal or near-normal life expectancy."
The disease was identified by - and named after - Dr James Parkinson who wrote 'An Essay On The Shaking Palsy' in 1817 which established it as a recognised medical condition.