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Scientists find it is possible to 'silence' chromosome that causes Down syndrome

Breakthrough causes mixed reactions within Down syndrome community

Published: Monday, Aug. 12 2013 2:25 p.m. MDT

Seventeen-year-old Hannah Gilbert, who has Down syndrome, was crowned prom queen at Sandy's Alta High School in 2011. Scientists at the University of Massachusetts Medical School have discovered a way to Seventeen-year-old Hannah Gilbert, who has Down syndrome, was crowned prom queen at Sandy's Alta High School in 2011. Scientists at the University of Massachusetts Medical School have discovered a way to "turn off" the genetic defect responsible for Down syndrome last month. (Tom Smart, Deseret News)

Researchers recently discovered how to "turn off" the genetic defect responsible for Down syndrome, but the breakthrough has elicited mixed reactions.

Last month, scientists at the University of Massachusetts Medical School announced they discovered a naturally occurring chromosome "off switch" that can "be rerouted to neutralize the extra chromosome responsible for trisomy 21, also known as Down syndrome, a genetic disorder characterized by cognitive impairment."

Although the researchers note that more research is needed, as they were only able to show the process of "turning off" the chromosome in a lab dish, the discovery "paves the way for researchers to study the cell pathologies and identify genome-wide pathways implicated in the disorder, a goal that has so far proven elusive." The research can give scientists insight into the basic biology of the syndrome. Details of the findings were published in the journal Nature.

"It’s so hard to imagine you could actually do that," Jawanda Mast, a mother of a 14-year-old daughter with Down syndrome, told NBC News. "Yes, I would take away the challenges, I would take away the health risks. But now I also stop and say, ‘Oh my goodness, how would that impact the rest of her?'"

People born without Down syndrome have 46 chromosomes in each cell (23 pairs), but those with Down syndrome have an extra copy of chromosome 21. Those with the extra chromosome have an increased risk for certain medical conditions such as congenital heart defects, respiratory and hearing problems, Alzheimer's disease, childhood leukemia and thyroid conditions. The new research could pave the way for future therapies for the condition.

The medical breakthrough has sparked mixed reactions among parents, advocates, ethicists and people with the condition. Among those is Dr. Brian Skotko, a medical geneticist and co-director of the Down Syndrome Program at Massachusetts General Hospital.

"If Down syndrome were completely cured, the world would lose something from the absence of that culture," Skotko, who has a sister with the condition, told NBC News. "There is something positive that people with Down syndrome contribute to the world."

Jeanne Lawrence, the professor of cell and developmental biology who led the research, said it likely wouldn't be possible to "cure" Down syndrome because the condition occurs at conception. The research would most likely used to target specific conditions of Down syndrome in people's early years, such as treating congenital heart disease in children.

Julie Cevallos, vice president of marketing for the National Down Syndrome Society, notes that the research is still in its early phases.

"When you go as far as a 'cure,' that’s when folks step back and go: 'We're not looking for a cure. We’re looking to help and support people with Down syndrome live healthy and productive lives,'" Cevallos, mother of a 5-year-old with the condition, told NBC News.

According to the National Down Syndrome Society, one in every 691 babies in the United States is born with Down's. Approximately 400,000 Americans currently have the condition and about 6,000 babies with Down syndrome are born in the United States each year. It is caused by the presence of an extra copy of chromosome 21 in 95 percent of cases.

Email: crenouard@deseretnews.com

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