People with Down syndrome might hold a key to cure Alzheimer's disease, according to new research.

Researchers at the University of Wisconsin-Madison's Waisman Center stated that the findings show why adults living with Down syndrome are more likely to develop the neurodegenerative disease.

The common symptoms of Down syndrome are poor muscle tone, short neck with excess skin at the back of the neck; flattened facial profile and nose; small head; ears and mouth; slanting of eye upwards mostly with a skin fold that comes out from the upper eyelid and covers the inner corner of the eye; white spots on the colored part of the eye (called Brushfield spots); wide, short hands with short fingers; a single, deep, crease across the palm of the hand; and a deep groove between the first and second toes.

There are more than 400,000 people living with Down syndrome in the United States.

The researchers examined the role of the brain protein amyloid-β in people with Down syndrome. They recruited 63 Down syndrome patients aged between 30 and 53. All participants were healthy adults without any clinical signs of Alzheimer's disease or other forms of dementia.

People with Down syndrome have an extra copy of 21 chromosome, where the gene that codes for the beta-amyloid protein resides.

The findings revealed that those with Down syndrome had high levels of amyloid-β protein but did not suffer the expected negative consequences of the elevated protein.

The team explained that participants with higher levels of amyloid-β did not show any difference in memory or cognitive function when compared to those without elevated levels of amyloid-β.

The team explained that it might also prove helpful to those without the syndrome.

"Our hope is to better understand the role of this protein in memory and cognitive function," lead study author Sigan Hartley, an assistant professor of human development and family studies at the University of Wisconsin-Madison, said in a press release. "With this information we hope to better understand the earliest stages in the development of this disease and gain information to guide prevention and treatment efforts.

"There are many unanswered questions about at what point amyloid-β, together with other brain changes, begins to take a toll on memory and cognition and why certain individuals may be more resistant than others."

The findings of the study are published in the journal Brain.