the team sifted through almost 10 billion pieces of DNA, looking for telltale genetic variants associated to the seven diseases.
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PARIS: The widest-ever genetic probe into inherited disease has identified at least 10 new genes linked to seven major ailments, such as diabetes, hypertension, coronary heart disease, bipolar disorder and rheumatoid arthritis.
Published today in the U.K. journal Nature, the study is being hailed as a vital gain in knowledge about the cause of these diseases and as a groundbreaking demonstration of the power of genomics.
The U.S. 15-million-dollar, two-year investigation by 200 British scientists entailed comparing and contrasting DNA samples from 17,000 Britons.
Working in 50 research institutions, the team sifted through almost 10 billion pieces of DNA, looking for telltale genetic variants associated to the seven diseases.
Gene-sifters
"Many of the most common diseases are very complex, part 'nature' and part 'nurture', with genes interacting with our environment and lifestyles," said Oxford University professor Peter Donnelly, who headed the consortium.
"By identifying the genes underlying these conditions, our study should enable scientists to understand better how disease occurs, which people are most at risk and, in time, to produce more effective, more personalised treatments."
The net cast by the gene-sifters covered 2,000 patients for each disease, making 14,000 samples. These were then compared with samples from 3,000 healthy individuals.
What they were looking for are so-called Snips – single-nucleotide polymorphisms (SNPs) – which are tiny flaws in the genetic code that can subtly affect the cascade of processes to make and repair the body's tissues.
Previous work by the consortium has already helped identify the clearest link yet to obesity and three new genes linked to Type 2 diabetes, a disease that is gaining epidemic proportions in many developed countries.
Another new insight is into bipolar disorder, previously known as manic depression, from which an estimated 100 million people around the world suffer.
The team exposed several balky genes among bipolar patients that, collectively, affect the way brain cells communicate with each other.
"Time of great optimism"
Nick Craddock of Cardiff University in Wales, which led the bipolar work, said the path was now open for better diagnostics for mental disease as well as new treatments, which could include drugs as well as education and advice on lifestyle choices.
"With the ongoing scientific advances in understanding of (bipolar) illness, we have the opportunity to make things very different for the next generation," said Craddock.
"This should be a time of great optimism for those individuals and families that have experienced illnesses like bipolar disorder, schizophrenia and depression."
The inquiry also yielded the first-ever genetic link between Type 1 diabetes and the inflammatory bowel disorder known as Crohn's disease. A gene called PTPN2 is common to both autoimmune diseases, which implies they share biological pathways.
The Wellcome Trust, a British medical research charity that funded the research, described the outcome was a dazzling show of genomics, the ability to unravel, compare and analyse the human genome for human benefit.
"Just a few years ago, it would have been thought wildly optimistic that it would be possible in the near future to study a thousand genetic variants in each of a thousand people," said the trust's director, Mark Walport. "What has been achieved in this research is the analysis of half a million genetic variants in each of 17,000 individuals, with the discovery of more than 10 genes that predispose to common disease."
