Is Parkinson’s hereditary? The role of genetics
Parkinson’s is a common neurodegenerative disease that affects millions of people worldwide. If someone in your family suffers from Parkinson’s disease, you may have wondered: am I also at risk of developing it? Is Parkinson’s hereditary? In this blog post, we will talk about the role of genetics in Parkinson’s disease. You will find out how this condition affects the nervous system, whether it runs in families, and what you can do to prevent it.
What is Parkinson’s disease?
Parkinson’s disease is a neurodegenerative disorder that affects several regions of the brain. It predominantly affects the substantia nigra, which controls balance and movement. The disease causes dopamine-producing brain cells (neurons) in this area of the brain to die. As a result, dopamine levels decrease, which leads to abnormal brain activity. The communication between the brain and the muscles weakens until the brain is no longer able to control certain movements.
The signs of Parkinson’s disease include trembling or shaking of a limb (tremors), rigidity or stiffness of limbs or torso, slow movement, and difficulties with balance and coordination. The symptoms slightly vary from person to person and gradually get worse over time.
Besides symptoms related to balance and movement, patients can also suffer from cognitive disturbances that have an impact on their daily lives. It’s not uncommon for people with Parkinson’s disease to experience impairment in cognitive processing, speed, attention, memory and response time.
Before we answer the question “Is Parkinson’s hereditary?”, let’s talk about treatment. Currently, there is no cure for Parkinson’s disease. Patients with Parkinson’s are usually older people, and by the time they start showing symptoms and are diagnosed, a large amount of their dopamine-producing neurons have already been damaged or destroyed.
While there is no known cure, there are treatment options for Parkinson’s – such as medication, surgical interventions, and lifestyle changes – that can help patients maintain a good or even great quality of life. Learn more about Parkinson’s treatment and how to manage this disease.
Is Parkinson’s genetic?
We don’t know what causes Parkinson’s disease. Genetics and environmental factors are both thought to play a role. Most likely, it’s a combination of the two that leads to a person developing Parkinson’s disease.
While researchers have identified genetic mutations that can be associated with the disorder, this does not mean that Parkinson’s disease is hereditary. Disease-causing genetic mutations do not necessarily run in families – they can be random alterations unique to the individual.
In fact, in the majority of cases, Parkinson’s disease is not inherited. Only 15-25% of people with Parkinson’s disease have a family history of this chronic illness. Studies have found that those who have a family history of Parkinson’s disease are 4-9% more likely to develop the condition than those who don’t.
While the heritability of Parkinson’s disease is fairly low, genes do appear to play an important role.
What’s the role of genetics in Parkinson’s disease?
There are two ways in which gene mutations can affect Parkinson’s disease: they can either directly cause the disorder (causal genes) or increase our susceptibility to it (associated genes). In the latter case, even if you have the associated gene mutation, you may never develop Parkinson’s disease.
Genes that have been linked to Parkinson’s disease include:
- SNCA: gene that provides instructions for making alpha-synuclein, a protein that can be found in large amounts in the brain, and smaller amounts in the heart, muscles and other tissues. At least 5 mutations of this gene have been found to cause Parkinson’s disease. These mutations can be inherited but they are extremely rare.
- PRKN: one of the largest human genes, which provides instructions for making a protein called parkin.
- PINK1: gene that provides instructions for making a protein called PTEN, which is found in high levels in the heart, muscles, and testes.
- LRKK2: gene that provides instructions for making a protein called dardarin. It’s active in the brain and other tissues.
- PARK7: gene that provides instructions for making the DJ-1 protein, which is found in many tissues and organs, including the brain.
- GBA: gene that provides instructions for making beta-glucocerebrosidase, an enzyme active in lysosomes.
- UCHL1: provides instructions for making an enzyme called ubiquitin carboxyl-terminal esterase L1, which is found in the brain.
So, is Parkinson’s hereditary? Inheritance patterns of these gene mutations vary and some of them are unknown, so it’s difficult to know whether people with a family history of Parkinson’s disease have an increased risk of developing it.
Depending on which genes are involved, Parkinson’s can be inherited from just one parent in an autosomal dominant pattern (LRRK2 and SNCA), or from both parents in an autosomal recessive pattern (PARK7, PINK1, and PRKN). In most cases, the parents of an individual with autosomal Parkinson’s disease each carry a copy of the altered gene but don’t show any symptoms themselves.
Genetic testing is available for some genes, including PINK1, PARK7, SNCA, and LRRK. Consult your doctor or your genetic counselor to find out whether genetic testing is a good option for you.
Some individuals may be more likely to inherit Parkinson’s disease than others. For example, people with early-onset Parkinson’s disease – which affects younger people and is usually diagnosed between the ages of 21 and 50 – are more likely to have inherited it than those who are diagnosed at a later age. Having a first-degree family member with Parkinson’s disease may also increase your risk of developing the condition.
Researchers have yet to identify variations in other genes that can be associated with Parkinson’s disease. When they do, we may know more about the extent to which Parkinson’s disease is hereditary.
How do gene mutations affect brain cells?
Now that we understand which gene mutations can affect Parkinson’s disease and that the disorder is caused by low dopamine levels affecting brain function, another question may come up. How do these genes cause neurons to die?
The explanation may be that gene mutations have an effect on the brain’s ability to break down unwanted proteins in dopamine-producing neurons. Consequently, the proteins that aren’t able to break down accumulate, damaging or destroying the brain cells.
In most cases of Parkinson’s disease, protein deposits called Lewy-bodies can be observed in neurons affected by protein buildup. We don’t know whether Lewy-bodies contribute to destroying nerve cells or if they’re part of the cells’ reaction to the disease.
Parkinson’s disease risk factors
Now that you know the answer to whether Parkinson’s disease is hereditary, let’s take a look at some risk factors other than certain gene mutations and a family history of the disease.
Risk factors of Parkinson’s disease (other than genetics) include:
- Being older. Parkinson’s disease is usually diagnosed above the age of 50.
- Being male. Men are more likely to have Parkinson’s disease than women.
- Exposure to toxins, such as herbicides and pesticides. It has been shown that people who are exposed to environmental pesticides have a higher risk of developing Parkinson’s disease.
- History of head trauma. Injury to the brain, neck or upper spine can increase the risk of Parkinson’s disease.
While Parkinson’s disease is genetic to an extent, these environmental factors also contribute to an individual’s risk.
Parkinson’s disease: prevention
Since we don’t know the exact causes of Parkinson’s disease, it’s difficult to find ways to prevent it. Nevertheless, there are certain lifestyle changes that are thought to help prevent – and treat – the disease.
For example, a compelling argument can be made in favor of exercise.
Studies that looked at tens of thousands of subjects have shown that people who exercise earlier in life – in their 30s and 40s – have a decreased chance of developing Parkinson’s disease when they’re older. In fact, intense exercise that gets your heart rate up seems to lower the likelihood of developing Parkinson’s disease by 30%.
However, these results must be taken with a grain of salt. There’s always the possibility of reverse causation: it could be that a very early, seemingly symptom-free version of the disease decreases people’s willingness or ability to exercise.
Parkinson’s exercises are highly recommended in the treatment. disease, too. Patients who are in good physical shape may have better muscle control and cognitive results, and they may also live longer.
Conclusion: Is Parkinson’s disease hereditary?
To answer the question “Is Parkinson’s hereditary?”, we looked at some of the possible causes of this common neurodegenerative disease. Scientists have discovered specific gene mutations that can cause Parkinson’s disease or increase our susceptibility to it, but these are seldom inherited. The most likely scenario is that a random gene alteration combined with certain environmental factors causes the disease. Researchers are working on identifying more gene mutations that could be potential culprits, as well as new methods of prevention, diagnosis, and treatment for Parkinson’s.