Chromosome that causes Down`s syndrome `switched off`

London: Researchers from the US have been able to correct the genetic fault that causes Down`s syndrome and as a result have raised the prospect of therapy for the disorder.

The researchers took cells from people suffering from the disorder and silenced the extra chromosome, which causes the condition, an English daily reported.

Scientists have lauded the new breakthrough and said that it was the first major step towards a `chromosome therapy.`

Jeanne Lawrence, who led the team at the University of Massachusetts, said that the findings will help accelerate understanding of the cellular defects in the disorder and if they can be treated with certain drugs.

She said that the long-range possibility is a chromosome therapy for Down`s syndrome, however, she said that it is 10 years or more away.

Her team used `genome editing` - a procedure allowing DNA to be cut and pasted, to drop a gene called XIST into the extra chromosome in cells taken from people suffering from the disorder.

Once in place, the gene causes a build-up of a version of a molecule called RNA that coats the extra chromosome and ultimately shuts it down.

The team also told how cells corrected for an extra chromosome 21 grew better, and developed swiftly into early-stage brain cells.

The writing has been published in the journal Nature.