“Gene scientists on Wednesday said that in lab-dish cells, they had found a way to switch off the rogue chromosome that causes Down’s syndrome. The breakthrough opens up the tantalising goal of therapy for Down’s, they said, cautioning that years of work lie ahead before this aim is reached — if, in fact, it is attainable. Down’s syndrome is the world’s leading genetically caused mental disease, accounting for around one in 600 live births in the United States. It is the first time that correction has been achieved for an entire chromosome, a coil of DNA that is studded with hundreds of genes, the protein-making codes to build and sustain life.”
http://www.rawstory.com/rs/2013/07/17/scientists-switch-off-chromosome-that-causes-downs-syndrome/