Why does Parkinson’s Disease Occur?

Ever wonder why does Parkinson’s disease occur?

This is mainly due to the damage to a specific brain part responsible for controlled body movements. This part is known as the substantia nigra. The substantia nigra carries a specialized group of cells that produce dopamine. Dopamine is a chemical messenger that helps the brain to correctly regulate various body movements. Since the brain in Parkinson’s disease no longer produces dopamine in sufficient amounts, the body movements become slow and abnormal. 

why does Parkinson's disease occur?

The typical symptoms of Parkinson’s disease include trouble walking, tremors, muscle stiffness, and rigidity. These symptoms develop when more than 50% of dopamine-producing cells are lost in the substantia nigra of the brain.  While the exact cause that leads to the death of these cells is unknown, researchers have found many factors that contribute to their death and ultimately develop the disease symptoms. These include genetic abnormalities and environmental factors.


Genetics is considered an important risk factor for Parkinson’s disease. Especially in patients diagnosed at a young age, genetics seems to play a big role.

Researchers have identified 15 faulty genes that are linked to Parkinson’s disease. 6 of these genes are directly involved in disease development and therefore have been widely studied.  These include SNCA, LRRK2, PRKN, PINK1, DJ-1, and ATP13A2.

In the case of SNCA or LRRK2, a mutation in one copy of the gene is sufficient to cause the disease symptoms. In all other cases, a mutation in both copies of the gene is required to cause the disease in a person.  

Some of these genes carry mutations that may develop the form of Parkinson’s disease that is not inherited.

Related post: Genetics and Parkinson’s disease – What’s the link?

Environmental Factors

Several environmental factors are linked to Parkinson’s disease. Some of these factors may directly cause the disease symptoms, others may increase the risk of developing it.

Environmental Toxins

Pesticides are among the leading environmental factors that contribute to the development of Parkinson’s disease.  Rotenone and paraquat are well-known pesticides that are strongly linked to Parkinson’s disease. These chemicals enter the body via inhalation, eating, drinking, or skin contact. Since farmers are more exposed to these chemicals, they have a high chance of developing Parkinson’s-like symptoms compared to others.

Besides pesticides, two potent toxins namely oxidopamine and MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) are also known to be the causative agents of Parkinson’s disease. Exposure to these chemicals has been shown to kill the dopamine-producing cells and cause changes in the brain similar to Parkinson’s disease. They are used in animal research to find possible therapies for Parkinson’s disease.

Related post: The five environmental causes of Parkinson’s disease

Diet-related Factors

The idea that diet might have a role in Parkinson’s disease is not new. Researchers have been studying the connection between Parkinson’s and diet for many years. They think that the lack of certain food components may increase the risk of developing Parkinson’s disease. 

Numerous studies have shown that people with coenzyme Q-10 and vitamin D deficiency are more susceptible to develop Parkinson’s symptoms than those who don’t. Parkinson’s patients are reported to have a reduced level of these components. Therefore, researchers are now trying to find whether their supplementation could help to treat the disease symptoms. 

Related post: Dietary supplements – Are they useful in Parkinson’s disease? 

Lack of Exercise

Exercise has become an important part of Parkinson’s disease development. Accumulating evidence suggests that there is a strong link between exercise and Parkinson’s disease and that those who do regular exercise are less likely to be affected by the disease than those who don’t.

While it is still uncertain how exercise could protect someone from developing Parkinson’s, researchers think that it may inhibit abnormal changes in dopamine-producing cells and contribute to the healthy functioning of brain parts involved in body movement.

Other Risk Factors

Age could also increase the chances of Parkinson’s disease. It is estimated that 1% of the population under the age of 60 is suffering from Parkinson’s disease and it reaches 5% over age 80.

Similarly, people with prior head injuries are also supposed to be at high risk for Parkinson’s disease. Many studies have reported a link between Parkinson’s and head injury, particularly traumatic brain injury.

People with traumatic brain injury have low dopamine levels in their brains and are more susceptible to developing the disease symptoms. 

Disclaimer: The information shared here should not be taken as medical advice. The opinions presented here are not intended to treat any health conditions. For your specific medical problem, consult with your health care provider.

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