Down Syndrome Chromosome "Silenced"

However:

Intervening in a live embryo is not likely, though. "I can't see how it could be done in all relevant cells in an embryo at the time Down's would be diagnosed," says Robin Lovell-Badge of London's National Institute of Medical Research.

Victor Tybulewicz, also at the NIMR, thinks the therapy's value will be in explaining what goes wrong. "It can be used to switch off the chromosome at different times, to understand if some consequences could be reversed," he says.

Elizabeth Fisher at University College London says it might be possible to treat some symptoms by silencing the chromosome in certain areas of the body.