Roughly 130,000 people in Arizona have Alzheimer’s disease, according to the Alzheimer’s Association.

Trials are under way nationwide to find a cure, including here in Phoenix. Barrow Neurological Institute is participating in 20 studies, including one aimed at people with Down syndrome.

By the time a person with Down syndrome is 60 or 65, there’s a more than 75 percent chance that person will have Alzheimer’s disease.

The reason said Dr. Marwan Sabbagh, who is leading this trial, is because of the extra copy of Chromosome 21.

Sabbagh said Chromosome 21 is the parent of the protein, amyloid, which is found in people with Alzheimer’s. And because people with Down syndrome already have that extra chromosome, amyloid accumulates at an accelerated rate.

"We know that by the time they’re 12, they start to show changes in their brain," Sabbagh said. "By 29, every single one of them will have Alzheimer’s changes in their brain. By age 35-40, we start to see imaging changes of amyloid in their brain.

Sabbagh said if the vaccine works, it would clear the amyloid from the body and immunize them from accumulating amyloid.