Researchers have recently discovered a genetic form of late-in-life Alzheimer’s disease that affects individuals who inherit two copies of a specific gene. The gene, known as APOE4, has long been recognized as a risk factor for Alzheimer's, particularly in older individuals. However, a new study suggests that for those carrying two copies of the gene, it serves as an underlying cause of the disease, leading to symptoms manifesting seven to 10 years earlier than in other older adults with Alzheimer’s.
Approximately 15% of Alzheimer’s patients carry two copies of the APOE4 gene, indicating a direct genetic link to the disease. This discovery challenges previous notions that genetic forms of Alzheimer’s only occur at younger ages, highlighting the importance of developing treatments that target the APOE4 gene.
Genetics and Alzheimer's Disease
Alzheimer’s disease affects over 6 million Americans and millions more globally, with the majority of cases occurring after the age of 65. While rare genetic mutations can cause early-onset Alzheimer’s, the APOE gene, with its three main variants (APOE2, APOE3, and APOE4), plays a significant role in late-in-life Alzheimer’s. APOE4, in particular, is considered the most significant genetic risk factor for the disease.
Research Findings and Implications
Studies using brain data and samples from thousands of individuals have shown that those with two copies of the APOE4 gene exhibit increased amyloid accumulation in the brain, a hallmark of Alzheimer’s. These individuals also tend to develop Alzheimer’s symptoms earlier, resembling a familial form of the disease.
While not everyone with two APOE4 genes develops Alzheimer’s, researchers are working to understand why. The findings have significant implications for Alzheimer's research and treatment, with a focus on developing targeted therapies and understanding the gene’s effects across diverse populations.
Future Directions in Alzheimer's Research
Current treatments like Leqembi may need to be tailored for individuals with two APOE4 genes due to their heightened risk of side effects. Research is also exploring gene therapy and drugs specifically targeting APOE4, as well as the importance of studying its effects in various ethnic groups.
While genetic testing is not yet recommended for the general population, it may be considered for those with a family history of early-onset Alzheimer’s. Understanding the genetic basis of Alzheimer’s opens new avenues for research and personalized treatment approaches.
