Gene breakthrough gives hope to Down’s sufferers

Scientists have taken the first step to finding a genetic treatment for Down’s syndrome by demonstrating that they can “switch off” the extra chromosome that causes the condition.

Children with Down’s syndrome are born with an extra copy of chromosome 21, rather than the usual two.

The ground-breaking laboratory tests, carried out in cell cultures, could also help to find treatments for secondary health problems associated with the condition, such as diseases of the bone marrow that can lead to leukaemia.

Till now, correcting the hundreds of genes over the extra chromosome using conventional gene therapy was not possible. But the new research, published in the journal Nature, uses a naturally occurring genetic switch, the XIST gene, that silences the entire chromosome.

Prof Jeanne Lawrence from the University of Massachusetts, who led the US research, hoped the “proof of principle” could lead to research on the concept of “chromosome therapy”.