The woman with Down syndrome who defied Alzheimer’s — and what it means for research

People with Down syndrome face a significantly higher risk of developing Alzheimer’s disease. By their mid-50s, most show signs of cognitive decline, and by their 60s, nearly 90% develop dementia. However, one woman with Down syndrome defied these odds, offering new insights into brain resilience.

Her case came to the attention of the Alzheimer Biomarker Consortium–Down Syndrome, a research initiative established in 2015 to examine Alzheimer’s disease biomarkers in individuals with Down syndrome. The consortium’s goal is to better understand the connection between the two conditions.

After enrolling in the consortium, the woman’s case stood out. For over a decade, researchers observed her as she exhibited all the physical markers of Alzheimer’s, such as amyloid plaques and tau tangles, but remained cognitively stable. Despite showing the typical neuropathology associated with Alzheimer’s, she continued to live independently, cooking, shopping, and socializing with no noticeable cognitive decline.

“Before she passed away, all the clinical assessments in our years of studying her indicated that she was cognitively stable, which is why this case is so fascinating,” said Dr. Jr-Jiun Liou, a neurologist at the University of Pittsburgh.

This was especially intriguing because, while some individuals without Down syndrome can carry Alzheimer’s pathology without symptoms, it is exceedingly rare for those with Down syndrome to avoid cognitive impairment.

In addition to her participation in the Alzheimer Biomarker Consortium–Down Syndrome, the woman had been part of two National Institutes of Health-funded longitudinal studies on Alzheimer’s in Down syndrome. Her decision to donate her brain after death allowed researchers to conduct a post-mortem examination, providing invaluable insights.

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Her brain was studied at the University of Pittsburgh’s 7T Bioengineering Research Program, where Dr. Liou performed high-resolution MRI scans. Despite significant Alzheimer’s-related brain changes, her cognitive abilities remained unaffected, raising questions about the relationship between Alzheimer’s pathology and cognitive decline.

Several factors may have contributed to her resilience. One possibility is her education—though her IQ was below average, she attended a private school for students with intellectual disabilities, which may have helped build cognitive reserve. Studies suggest that higher education levels can delay the effects of neurodegeneration.

Genetics may have also played a role. Some individuals with Down syndrome have mosaicism, where only some of their cells have an extra copy of chromosome 21. If this woman had mosaicism, it could have influenced her brain’s ability to resist Alzheimer’s-related decline.

Additionally, physiological differences may have helped protect her brain. Researchers believe she may have had a surplus of brain tissue or genes that helped manage damaged proteins more effectively, slowing Alzheimer’s progression.

Her case has sparked excitement among researchers, who hope it could lead to new strategies for preventing or slowing the disease.

“If we can identify the genetic underpinnings or lifestyle factors that allowed her brain to function well despite the pathology, we may uncover strategies that could benefit others,” said Dr. Elizabeth Head, a neuroscientist at the University of California, Irvine. “This study shows how just one person’s participation in research can lead to profound discoveries,” Head emphasized.

As research continues, this case offers hope for individuals with Down syndrome and the broader population at risk for Alzheimer’s. If insights from her case help identify protective factors, they could lead to new diagnostic and treatment options for dementia.

Unfortunately, societal attitudes toward persons with disabilities — especially when they are prenatally diagnosed — must change. If children in the womb are intentionally destroyed due to their genetic conditions, there can be no progress or cures, when death is used as the primary means of “prevention.”