Parkinson's is the second most common neurodegenerative disease in the world, after Alzheimer's. For this reason, a diagnosis in a family member causes understandable fear. However, the vast majority of cases do not have an identifiable genetic cause, nor are they transmitted directly from parents to children.
How hereditary is Parkinson's?
In Parkinson's, it is important to clearly distinguish between "genetic" and "hereditary," because they do not mean exactly the same thing. A disease having genetic factors means that certain genes may influence the risk of developing it. But being hereditary means there is a specific genetic alteration that can be passed from one generation to the next with a clearer pattern. And this, in Parkinson's, occurs only in a minority of cases.
In general, it is estimated that between 85% and 90% of Parkinson's cases are sporadic. That is, they appear in a specific person without there being an identifiable genetic mutation or multiple clear cases within the family.
Only between 5% and 10% of all cases are related to mutations in specific genes that can be transmitted to the next generation. These are the cases we usually call familial or hereditary forms of Parkinson's.
In addition, approximately 15% of people with Parkinson's have an affected first-degree relative, such as a mother, father, sister, or brother. But this does not necessarily mean there is a direct inheritance. In many cases, it reflects a polygenic predisposition, that is, the sum of many genes with small effects that can slightly increase the risk, especially if combined with other environmental or lifestyle factors.
How do I know if my family's Parkinson's is hereditary?
As we have seen before, in most cases the disease is not hereditary, even if we have a relative with Parkinson's. When we speak of hereditary Parkinson's, it is in cases where there is a concrete connection to a gene related to the disease. And even then, when there is a genetic variant associated with Parkinson's, it does not always mean that the person will develop the disease.
Among the best-known genes related to genetic Parkinson's, we can distinguish:
- Genes with dominant inheritance: in which a single altered copy of the gene can increase the risk or cause the disease in some families. These include, above all, LRRK2, SNCA, and VPS35. The LRRK2 gene is one of the most studied and is one of the most frequent genetic causes of familial Parkinson's. Even so, not everyone with a variant in LRRK2 develops Parkinson's, because the penetrance (the probability that a genetic variant will eventually manifest as a disease) can be incomplete.
- Genes with recessive inheritance: in which normally two altered copies of the gene are needed, one inherited from each parent, for the disease to appear. This group includes PRKN, also known as Parkin, PINK1, and PARK7. They are usually more related to early-onset forms of Parkinson's, especially when symptoms appear before age 50.
- The GBA gene: variants in this gene are not usually considered a direct hereditary cause in the same sense as some classic familial mutations, but they are one of the most important known genetic risk factors for Parkinson's.
It is not recommended to get a genetic test out of curiosity or just because there is an isolated case in the family. The prudent thing to do is to discuss it first with neurology or a genetic counseling unit, especially if:
- There are several people affected in the same family, especially across different generations
- The diagnosis appeared at an early age, for example, before 50
- The family pattern appears to repeat with some clarity, generation after generation
How to prevent Parkinson's: modifiable risk factors
Although Parkinson's cannot always be prevented, environmental and lifestyle factors play a significant role in how the risk is expressed:
- Regular aerobic exercise: This is one of the measures with the greatest scientific support for caring for the brain and nervous system. In general, a minimum of 150 minutes per week of moderate aerobic activity is recommended, such as brisk walking, swimming, dancing, or cycling. Studies show that exercise protects against neurodegeneration, improves brain health, and maintains mobility.
- Mediterranean diet: Rich in antioxidants, omega-3, fruits, vegetables, and olive oil. Flavonoids (blueberries, dark chocolate, tea, strawberries) have been studied for their potential to reduce mortality in people with Parkinson's. Conversely, the consumption of processed foods and saturated fats should be limited.
- Stress management: Sustained stress is not only noticeable in one's mood; it can also affect the nervous system. When we live with high levels of cortisol (the hormone released in stress situations) for too long, the brain works in a state of constant alertness. Therefore, incorporating simple tools such as meditation, yoga, and deep breathing are a very good way to take care of brain health.
- Avoid environmental toxins: Prolonged exposure to pesticides and heavy metals is associated with a higher risk of Parkinson's. Reducing this exposure is especially relevant for people in agricultural or industrial jobs.
- Social life and cognitive stimulation: Social interaction, reading, strategy games, and continuous learning promote brain health.
