Updated: Oct 20
When a parent is diagnosed with Alzheimer's disease, it's natural for concern to arise about the possibility of inheriting the condition. However, it's important to dispel the misconception that having a parent with Alzheimer's automatically predisposes an individual to develop the disease. In reality, the risk of developing Alzheimer's disease is influenced by various factors, including the age of onset and family history. By understanding these nuances, we can gain clarity and alleviate unnecessary anxiety surrounding our own potential risk.
Early Onset vs. Late Onset:
Alzheimer's disease can be classified into two main types: early onset and late onset. Early onset Alzheimer's disease is relatively rare and typically occurs when symptoms manifest between the ages of 40 and 50. In these cases, a genetic variant of Alzheimer's is often responsible, and the risk of inheriting the condition from an affected parent is higher. However, it's essential to note that early onset Alzheimer's accounts for a small percentage of overall cases.
On the other hand, the most common form of Alzheimer's disease is late onset, which typically emerges after the age of 65. For individuals whose parents develop late onset Alzheimer's, the risk of developing the disease is not significantly different from those without a parental history of Alzheimer's. In other words, having a parent with late onset Alzheimer's does not necessarily increase the individual's risk of developing the condition.
The Limitations of Genetic Testing:
In the face of a late-life dementia diagnosis in the family, individuals often contemplate undergoing genetic testing to determine their own risk of developing Alzheimer's disease. However, it's crucial to understand that the presence of a specific gene associated with Alzheimer's, such as APOE4, does not guarantee the onset of the disease. Genetic testing can provide information about the presence of certain gene variants linked to Alzheimer's, but it cannot definitively predict an individual's fate.
Age as the Primary Risk Factor:
When considering the risk factors for Alzheimer's disease, age emerges as a significant determinant. Advancing age is the strongest predictor of developing the condition, as it significantly raises the chances of diagnosis. Individuals in their 70s face approximately a 40% risk of being diagnosed with Alzheimer's disease, which is more than twice the likelihood compared to those in their 60s. Family history, in comparison, contributes a relatively small increase of 20-30% to the overall risk, emphasizing the paramount importance of age as a risk factor.
Having a parent with Alzheimer's disease does not necessarily mean that one is predestined to develop the condition. Understanding the distinction between early onset and late onset Alzheimer's provides valuable insights into the potential genetic influence on risk. However, for most individuals with a late-onset parental history, the risk remains similar to those without such a family history. Age remains the most significant risk factor for Alzheimer's disease, overshadowing the impact of familial ties. It is essential to seek accurate information, dispel misconceptions, and focus on adopting a proactive approach to brain health through lifestyle choices and early intervention. Remember, knowledge empowers us to make informed decisions and lead fulfilling lives, regardless of our familial medical history.
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Domenico Praticò, MD, is the Scott Richards North Star Charitable Foundation Chair for Alzheimer’s Research, Professor and Director of the Alzheimer’s Center at Temple, and Professor of Pharmacology at the Lewis Katz School of Medicine at Temple University