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A new study from the University of Southern California (USC) Leonard Davis School of Gerontology has uncovered a significant clue as to why individuals with Down syndrome are more likely to develop Alzheimer’s disease earlier and with greater severity than the general population: excess iron in the brain.
Researchers found that people with both Down syndrome and Alzheimer’s disease (DSAD) had twice as much iron in the prefrontal cortex—a region responsible for memory, planning, and decision-making—compared to those with only Alzheimer’s or neither condition. This iron accumulation was linked to increased oxidative stress and damage to cell membranes, accelerating the progression of the disease.
“This is a major clue that helps explain the unique and early changes we see in the brains of people with Down syndrome who develop Alzheimer’s,” said Max Thorwald, lead author of the study and a postdoctoral fellow at USC. He noted that while it has long been known that people with Down syndrome are at higher risk for Alzheimer’s, the new findings shed light on how iron overload may exacerbate the condition.
Why Is Iron a Problem?
Down syndrome is caused by an extra copy of chromosome 21, which includes the APP gene. This gene is responsible for producing amyloid precursor protein, which in turn leads to the formation of amyloid-beta plaques—a hallmark of Alzheimer’s disease. With three copies of the APP gene, individuals with Down syndrome produce more amyloid-beta, and about 50% show signs of Alzheimer’s by age 60, roughly two decades earlier than the general population.
The study revealed that DSAD brains not only had higher iron levels but also showed more signs of microbleeds—tiny leaks in brain blood vessels—which are more common in DSAD patients. Additionally, the brains had lower activity of enzymes that protect against oxidative damage, especially in critical membrane regions known as lipid rafts, making cells more vulnerable to a destructive form of cell death called ferroptosis.
New Avenues for Treatment
The researchers believe that therapies targeting iron accumulation and oxidative stress could help slow the progression of Alzheimer’s in people with Down syndrome. Early animal studies have shown promise for iron-chelating drugs, which bind to and help eliminate excess iron from the body, in reducing Alzheimer’s-related damage.
“This study gives us a clearer picture of what’s going wrong in the brain, and that’s the first step to finding better treatments,” said Caleb Finch, senior author and University Professor Emeritus at USC.
Disclaimer:
This article is based on recent scientific research and is intended for informational purposes only. The findings discussed are preliminary and should not be interpreted as medical advice. Individuals concerned about Alzheimer’s disease or Down syndrome should consult qualified healthcare professionals for diagnosis and treatment options.
