Scientists silenced the extra copy of a chromosome that causes Down syndrome in laboratory stem cells, offering the first evidence that it may be possible to correct the genes responsible for the disorder.

The findings, published Wednesday in the journal Nature, offer new cell models for developing potential treatments, researchers said.

The models, aided by gene-manipulating technology from Sangamo Biosciences Inc., may help researchers discover drug targets for other ill health effects that come with the syndrome, including heart disease, hearing difficulties and weakened muscles.