Are Down syndrome and Alzheimer’s linked? Seeking the answer is her life’s work
By SHERRY HALBROOK
Sometimes we may work diligently and successfully for many years with little fanfare, and then suddenly the clouds clear and we’re in the spotlight.
Dr. Sharon Krinsky-McHale, a research scientist 5 at the state Institute for Basic Research in Developmental Disabilities, knows what that feels like. After 20 years of research, she was recently recognized as the IBRDD 2017 Employee of the Year.
She’s been there since 1995 when she received her doctoral degree at The City University of New York Graduate Center. Like many research scientists, she has spent the ensuing decades patiently investigating a fascinating but elusive question. For her, it has become finding and understanding the connection between Down syndrome, which presents at birth, and dementia, which presents in adulthood.
Down syndrome is a genetic condition that causes delays in physical and intellectual development. It occurs in 1 of every 792 live births. Individuals with Down syndrome have 47 chromosomes, instead of the usual 46. Research indicates Alzheimer’s also can be caused by certain genetic abnormalities, but may be triggered in some people by physical trauma to the brain and other health issues.
Not everyone who has Down syndrome eventually develops dementia, but many do. And, of course, not every adult with dementia has Down syndrome. But the data strongly suggests there is a link, and understanding it will shed valuable insight into how our brains function and the role genes play.
Dr. Krinsky-McHale, who is now part (a principal investigator) of a nationwide research effort funded by the U.S. National Institutes of Health, said they now believe having the third copy of chromosome 21 that characterizes “complete” Down syndrome may be an important factor in understanding the link between the two conditions.
Adults with Down syndrome are far more likely to develop Alzheimer’s disease in middle age compared with most other people.
However, that tendency was not apparent in the 1940s when the average life expectancy was just nine years for a person with Down syndrome. Now that research and care have dramatically improved, the average life expectancy for this group is age 60 and the onset of dementia in their forties or fifties is a growing challenge..
“Some now live into their late sixties and early seventies,” Krinsky-McHale said. “And we have one participant in our study who is 81. He has complete Down syndrome, but he does not have dementia.” Why he has not developed it when so many others have is an intriguing and important question she and other researchers want to answer.
Why are people with Down syndrome more likely to develop Alzheimer’s disease and at an earlier age than the general population? And why do some people with Down syndrome never develop Alzheimer’s? When they discover the answers to these questions, the potential for developing effective treatments or even preventing these conditions may be greatly advanced.
Krinsky-McHale’s research has found adults who are in the early stages of dementia show a high frequency of specific neuropsychiatric symptoms compared to their unaffected peers.
“For example, individuals with symptoms of depression may be at an even higher risk of progressing to dementia than those without depression,” she said.
This knowledge can provide insights into the amounts and types of supports persons with Down syndrome will need in the future.
The 200-300 volunteers who participate in the current research are all adults with Down syndrome 40-85 years of age and are largely drawn from the broader New York City tristate area, the greater Boston and the Los Angeles areas.
In addition to Krinsky-McHale, the national team of scientists (Alzheimer’s Biomarkers Consortium of Down Syndrome) comes from Columbia University’s Medical Center in New York, the Kennedy Krieger Institute and Johns Hopkins University (Baltimore), the University of California- Irvine (Irvine), the Massachusetts General Hospital/Harvard (Boston), and the University of North Texas Health Center (Fort Worth). The team includes neurologists, geneticist, neuroscientists, epidemiologists and psychologists, all working closely together.
What motivates her to stick with this research?
“It’s very exciting to see our understanding grow,” Krinsky-McHale said. “I came to the IBR immediately after finishing my doctorate and found the study of aging in adults with Down syndrome so extremely intriguing that I have devoted my life’s work to this special population of adults.
“We have been seeing some of the same individuals with Down syndrome for the last 22 years,” she said. “I saw them when they were young and healthy and now I see them in decline and developing dementia. It’s heartbreaking. It’s particularly cruel for someone who has been dealing with developmental disabilities their entire life to face an early onset of Alzheimer’s.
“There’s so much more that needs to be done.”