New York City – In a cruel coincidence that scientists do not yet fully understand, research has shown that people with Down syndrome, a chromosomal abnormality, have a much higher incidence of Alzheimer’s disease at an early age. Some studies have said that 60 to 75 percent of people over age 60 with Down syndrome will have Alzheimer’s, though Dr. Ira Lott, who is in charge of the Down syndrome program at the School of Medicine at the University of California, Irvine, said those studies have been limited in scope.
So as advances in health care have extended the average life expectancy of people with Down syndrome to more than 50 years today from 25 in 1983, doctors and family members are now struggling to cope with a double dose of disability.
Dr. Philip Levy, president of the Manhattan-based YAI/National Institute for People with Disabilities, said Alzheimer’s theft of memory and communication skills is particularly devastating for people with Down syndrome, who have a lower-than-average I.Q. but can make friends easily.
“Their social skills are one of the things that makes them feel very important; they get a lot of positive attention for that,” Dr. Levy noted. “So, when that is taken away, it is very, very cruel.”
There are about 350,000 people with Down syndrome in the United States. They have an extra copy of the 21st chromosome, which carries genes for the production of a protein, beta-amyloid. Overproduction of that protein results in what are known as amyloid plaques in the brain, which can manifest as Alzheimer’s disease and alter memory and brain function.
By age 40, all people with Down syndrome have the amyloid plaques in their brains, though not all develop Alzheimer’s symptoms immediately. Some people with Down syndrome live into their 50s, 60s and even 70s without ever actually contracting the disease.