LAST October a discovery was made that brought hope to millions of sufferers from chronic fatigue syndrome (CFS). A group of researchers found a bug with the long-winded name of xenotropic murine leukaemia virus-related virus (XMRV) in 67% of American patients with CFS (as opposed to 4% of healthy controls). This figure increased dramatically when the patients were retested.

The news was exciting for patients because CFS is a debilitating disorder of long-term tiredness for which there is no simple explanation, and certainly no sniff of a cure. It has even attracted a certain degree of media scepticism—being dubbed, at one time, “yuppie flu”.

A critically ill Turkish boy has had his life saved after scientists were able to read his genome quickly and work out that he had a wrong diagnosis.

"This study shows how we've arrived at a turning point in the genetics of disease.

"Previously, finding DNA changes was painstakingly slow.

"Now, with new DNA sequencing technologies, a trickle of newly identified disease genes will soon become a flood.

"This will be helped by knowing the genomes of many people who are not known to have particular diseases because then we can separate DNA changes that cause disease from those that do not."

"This is an interesting study - lots of groups are now using the power of new methods for sequencing the human genome to find DNA changes that underlie rare diseases (and increasingly for common diseases too).

"For practical reasons, many groups are concentrating at first on the 1% of the genome which codes for proteins which is what they have done here."