Researchers have unveiled a potentially groundbreaking classification for individuals carrying two copies of the APOE4 gene. This genetic makeup may not just increase the risk of Alzheimer's, but rather define a distinct genetic form of the disease, signaling earlier symptom onset.
Published in Nature Medicine, the study challenges previous understandings by proposing that APOE4 homozygotes are almost inevitably destined to develop Alzheimer's if they reach an advanced age. Sterling Johnson from the University of Wisconsin's Alzheimer's Disease Research Center highlighted the significance of these findings, suggesting a paradigm shift in how the condition is approached.
For decades, the presence of two APOE4 variants has been linked to a heightened risk of Alzheimer's compared to the more common APOE3 variant. This study expands on that knowledge by demonstrating that approximately 95% of APOE4 homozygotes exhibit abnormal beta amyloid protein levels by age 65, a hallmark of Alzheimer's, and 75% show positive brain scans for amyloid.
Juan Fortea and his team from the University of Barcelona analyzed over 3,000 donated brains and clinical data from more than 10,000 individuals across three countries. Their research suggests that the consistent biological markers and predictable symptom progression in APOE4 homozygotes meet the criteria for defining Alzheimer's as a genetic disease in these cases.
However, not all experts are convinced. Professor David Curtis from the UCL Genetics Institute expressed skepticism, noting that the disease processes appear similar regardless of APOE4 variants carried. \"No matter how many copies of APOE4 one carries, the underlying disease processes seem similar across cases of Alzheimer's disease,\" Curtis stated.
This ongoing debate underscores the complexity of Alzheimer's research and the quest to unravel its genetic underpinnings, potentially leading to more targeted diagnostic and therapeutic strategies in the future.
Reference(s):
People with two copies of a risk gene have genetic form of Alzheimer's
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