Iron Link Found ⁤between Down Syndrome,⁤ Alzheimer’s Disease

‍ updated june 21, 2025

Los Angeles – USC Leonard Davis School of Gerontology scientists have pinpointed a connection between high brain iron and increased cell damage‍ in individuals with both Down ⁢syndrome ⁢and Alzheimer’s disease. The research highlights a ‍potential‍ factor accelerating Alzheimer’s symptoms in those‍ with Down syndrome.

The study revealed that⁣ brains of⁢ individuals ⁤with Down syndrome ‍and⁤ Alzheimer’s (DSAD) contained‍ twice the iron and exhibited more oxidative‍ damage to cell membranes compared to ⁢those with Alzheimer’s alone or neither condition. These results suggest an iron-mediated cell death process,potentially explaining the earlier and more severe Alzheimer’s symptoms in people with Down syndrome.

Max⁣ Thorwald, the study’s lead author, said⁣ the findings offer a “major clue” to understanding the unique⁤ brain changes in people with Down syndrome who develop Alzheimer’s.⁤ He added that while the increased likelihood of Alzheimer’s in this population has been⁤ known, the role of⁤ increased brain iron is now becoming clearer.

Down syndrome results from an extra copy of chromosome 21, which includes the amyloid precursor protein (APP) gene. This gene is linked to amyloid-beta (Aβ) production, the protein forming plaques in Alzheimer’s ⁤brains. Individuals with Down syndrome⁢ produce‍ more of this protein due to the extra gene copy. By age 60, about⁢ half of ⁤those with Down⁢ syndrome show Alzheimer’s signs, roughly 20 years earlier than the general population.

Caleb Finch, the study’s senior ⁤author, emphasized the importance of understanding Down syndrome biology for Alzheimer’s research.

The research team analyzed brain tissue from individuals with alzheimer’s, DSAD, and those without either condition,‍ focusing on the prefrontal cortex. Key discoveries included:

• DSAD brains had twice the iron in the prefrontal cortex compared to other groups.This buildup is believed to stem from⁣ microbleeds, tiny brain blood vessel leaks, more common in DSAD and linked to higher APP amounts.
• DSAD brains showed more damage to lipid-rich cell membranes, indicated by⁣ higher levels of lipid peroxidation byproducts.
• Antioxidant defense systems were weaker in DSAD brains, particularly in lipid rafts, areas of the cell membrane.

Thorwald explained that these findings point to increased ferroptosis,a cell death type driven ‍by iron-dependent lipid peroxidation. “Essentially, iron builds up, drives the ⁣oxidation that damages cell membranes, and overwhelms the ⁢cell’s ability to protect‍ itself,” he said.

Lipid rafts in DSAD brains showed more oxidative damage, fewer protective enzymes, and increased activity of⁢ β-secretase, an enzyme interacting with ‍APP⁤ to produce Aβ proteins.Finch ⁣said this combination ‍may accelerate amyloid plaque growth, speeding up Alzheimer’s progression in people with Down syndrome.

Studying rare cases of mosaic or partial Down syndrome, where the extra chromosome 21 copy is present in fewer cells, revealed lower APP and iron levels, and ⁢longer lifespans. Conversely,⁢ those with full trisomy 21 and DSAD had shorter lifespans ⁢and more brain damage. Finch said these⁣ cases support‍ the idea that APP and associated iron levels substantially⁤ impact disease progression.

What’s next

The team suggests their findings could inform future treatments, especially for those with Down syndrome ⁣at high Alzheimer’s risk. Thorwald noted that‍ early mouse studies suggest iron-chelating treatments, which remove iron from the body, may reduce Alzheimer’s pathology indicators. He added that medications ⁢targeting brain iron removal or⁢ strengthening antioxidant systems could offer new hope, emphasizing the importance of addressing⁤ factors hastening plaque growth⁣ alongside amyloid plaques themselves.