Scientists have recently discovered that a familial form of Alzheimer’s disease may be a separate disease rather than an offshoot. This inherited form of Alzheimer’s may be more common than previously thought, accounting for about 1 in 6 cases. Researchers have found that a form of the APOE gene may be key to genetic testing in determining treatments for Alzheimer’s. They have identified different forms of the APOE gene, with APOE4 increasing the risk of developing Alzheimer’s. Individuals with two copies of APOE4 have an elevated risk and may be considered to have a genetic form of Alzheimer’s.
A study compared people with two copies of the APOE4 gene to those with other types of the APOE gene. Researchers found that individuals with two copies of APOE4 developed Alzheimer’s about 10 years earlier than those with other forms of the disease. The onset of the disease was approximately at age 65 for those with the inherited form of Alzheimer’s. People with two copies of APOE4 also had a higher risk of having beta-amyloid and tau build-up in the brain, indicating a genetic form of the disease. The study suggests that genetic testing for APOE4 can help in identifying individuals at higher genetic risk for Alzheimer’s.
Approximately 30% to 35% of people with two copies of APOE4 may develop at least mild cognitive impairment or dementia, according to a previous study. However, APOE4 is also strongly associated with heart disease, which may have led to some individuals dying from cardiovascular disease before developing dementia. It is estimated that 15% of people diagnosed with Alzheimer’s have two copies of the APOE4 gene, making it one of the most prevalent inherited diseases. Lifestyle and environmental factors also play a role in the development of Alzheimer’s in individuals with APOE4.
One treatment for Alzheimer’s is lecanemab, which helps 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 crucial for personalized treatment. Physicians may consider recommending genetic testing for patients with Alzheimer’s to determine their risk assessment and potential response to treatment. Some treatment centers do not offer medications like lecanemab due to the risk of brain swelling in individuals with two copies of APOE4. Understanding the genetic factors associated with Alzheimer’s may lead to novel care models and therapeutic opportunities to prevent and cure this devastating disease.