Genetic testing is becoming increasingly important in determining treatments for Alzheimer’s disease, according to experts. Scientists have recently discovered that a familial form of Alzheimer’s disease may actually be a separate disease rather than a subtype. This inherited form of Alzheimer’s may be more common than previously believed, with researchers suggesting that it could account for 1 in 6 cases. The APOE gene is considered to be a key factor in genetic testing for Alzheimer’s, with different forms of the APOE gene affecting an individual’s risk of developing the disease. Specifically, having two copies of the APOE4 gene is associated with an increased risk of developing Alzheimer’s.
The new study comparing people with two copies of the APOE4 gene to those with other forms of the APOE gene found that the disease appeared about 10 years earlier in those with two copies of APOE4, with onset around age 65 on average. These individuals also experienced more severe symptoms at an earlier age compared to those with other forms of Alzheimer’s. Having two copies of the APOE4 gene was also linked to a higher risk of developing beta-amyloid and tau build-up in the brain. Researchers believe that people with two copies of APOE4 have a genetic form of Alzheimer’s, which could have implications for risk mitigation and precise management of the disease.
Although around 30% to 35% of individuals with two copies of the APOE4 gene are expected to develop mild cognitive impairment or dementia, this gene is also strongly associated with heart disease. Therefore, it is possible that some individuals with two copies of APOE4 may have died from cardiovascular disease before developing dementia. The study suggests that around 15% of individuals diagnosed with Alzheimer’s may have two copies of the APOE4 gene. Despite the genetic predisposition, not everyone with APOE4 will necessarily develop Alzheimer’s, as other factors such as lifestyle and environment also play a role.
Physicians do not routinely request genetic testing for individuals diagnosed with Alzheimer’s, but the study authors suggest that this type of testing could be beneficial in determining treatment options. For example, genetic testing could be crucial for helping individuals with two copies of APOE4 make informed decisions about treatments like lecanemab, which aims to clear amyloids in the brain. However, individuals with two copies of APOE4 are more likely to experience brain swelling from these medications, making genetic testing potentially life-saving in this context. Some treatment centers do not offer this medication due to the associated risks.
In conclusion, genetic testing for Alzheimer’s disease is becoming increasingly important as researchers uncover new insights into the genetic factors that influence an individual’s risk of developing the disease. The discovery that a familial form of Alzheimer’s may be a separate disease has significant implications for risk assessment and treatment strategies. Individuals with two copies of the APOE4 gene have an increased risk of developing Alzheimer’s and may benefit from genetic testing to inform their healthcare decisions. Ultimately, these findings may lead to more personalized approaches to managing and preventing Alzheimer’s disease.
