The genetics behind Alzheimer’s and Parkinson’s diseases

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Alzheimer’s and Parkinson’s diseases are two of the most common neurodegenerative disorders, affecting millions of people worldwide.

While the exact causes of these diseases are not fully understood, researchers have made significant progress in identifying genetic factors that increase the risk of developing these conditions.

This review provides a clear overview of what we know about the genetic predispositions to Alzheimer’s and Parkinson’s diseases, making complex genetic information accessible to non-scientists.

Alzheimer’s disease is primarily associated with memory loss and cognitive decline, while Parkinson’s disease is known for its impact on movement, causing tremors and stiffness.

Both diseases typically develop later in life, and both have been linked to a combination of genetic and environmental factors.

Alzheimer’s Disease Genetics

For Alzheimer’s, the most well-known genetic risk factor is the APOE gene. This gene comes in several different forms, but one variant known as APOE e4 is linked to an increased risk of the disease. If a person inherits one copy of APOE e4, their risk of developing Alzheimer’s increases.

If they inherit two copies (one from each parent), the risk increases even more. However, having the APOE e4 gene does not mean that Alzheimer’s is guaranteed; it only affects the likelihood of developing the disease.

Researchers have also identified other genes associated with Alzheimer’s, especially in rare, familial forms of the disease that appear earlier in life (before age 65).

These genes include APP, PSEN1, and PSEN2. Mutations in these genes can lead to the production of abnormal proteins that are toxic to brain cells, but these mutations are relatively rare.

Parkinson’s Disease Genetics

In Parkinson’s disease, several genes have been identified that influence the risk. One of the most significant is the LRRK2 gene, where certain mutations can lead to an increased risk of developing Parkinson’s, especially in certain ethnic groups such as Ashkenazi Jews and North African Arabs.

Another important gene is SNCA, which affects the production of the protein alpha-synuclein. Abnormal accumulation of this protein in the brain is a hallmark of Parkinson’s disease.

Other genes linked to Parkinson’s include PARK2, PARK7, PINK1, and DJ-1, which are particularly associated with younger-onset forms of the disease.

These genes are involved in the functioning of mitochondria (the energy-producing structures in cells) and the clearing of damaged cells, suggesting that disruptions in cellular energy and waste management are key factors in the disease’s development.

Implications of Genetic Findings

Understanding the genetics behind Alzheimer’s and Parkinson’s diseases helps researchers develop potential treatments that target specific genetic pathways.

For example, drugs that can reduce the production of toxic proteins or enhance the clearing of damaged cells are currently being investigated.

However, it’s important to remember that genetics is only part of the story. Environmental factors such as diet, exercise, exposure to toxins, and overall lifestyle also play significant roles in the development of these diseases.

This means that genetic predisposition does not determine destiny; it only influences risk.


In conclusion, while genetic factors can increase the risk of developing Alzheimer’s and Parkinson’s diseases, they do not guarantee that these diseases will occur. Ongoing research continues to uncover more about how these genetic factors interact with each other and with environmental influences.

This growing understanding holds the promise of more effective prevention strategies and treatments in the future, offering hope to those at risk of these debilitating conditions.

If you care about Alzheimer’s disease, please read studies that bad lifestyle habits can cause Alzheimer’s disease, and strawberries can be good defence against Alzheimer’s.

For more information about brain health, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.

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