The largest-ever study of the genetics behind diseases has found 24 genetic risk factors -- half of them completely new -- linked to seven common diseases, British scientists announced Wednesday.
The discoveries are the biggest identification yet of disease-associated genes, and could one day help researchers decipher the biology of major illnesses, perhaps leading to more effective drugs.
The Wellcome Trust Case Control Consortium has been studying the genetics behind some of most common and mysterious diseases. The consortium has examined DNA samples from 17,000 people across the United Kingdom, bringing together 50 research groups and 200 scientists in the field of human genetics from dozens of U.K. institutions.
Over two years, they have analyzed almost 10 billion pieces of genetic information as they compared the genomes of diseased and healthy volunteers.
The researchers have been able to identify more of the genes known to play a role in the development of:
- Crohn's disease
- Rheumatoid arthritis
- Type 1 diabetes
- Type 2 diabetes
- Bipolar disorder
- Coronary heart disease
- Hypertension
Scientists have known for years that the causes of our most common diseases are a combination of lifestyle and interaction with our environment, and genetic predisposition. But researchers have been trying to work out which parts of the genome -- the 3 billion sub-units of DNA in our cells -- are actually responsible for each disease.
"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 personalized treatments," says University of Oxford Professor Peter Donnelly, who has led the Wellcome Trust Case Control Consortium.
"We are just scratching the surface," Donnelly told reporters.
The findings are published in the journals Nature and Nature Genetics.
Among the most significant new findings are four chromosome regions containing genes that can predispose a person to Type 1 diabetes, and three new genes for Crohn's disease. For the first time, the researchers have found a gene linking these two autoimmune diseases, known as PTPN2.
"The link between type 1 diabetes and Crohn's disease is one of the most exciting findings to come out of the Consortium," says University of Cambridge Professor John Todd, who led the study into type 1 diabetes.
"It is a promising avenue for us to understand how the two diseases occur. The pathways that lead to Crohn's disease are increasingly well understood and we hope that progress in treating Crohn's disease may give us clues on how to treat type 1 diabetes in the future."
Research from the Consortium has already played a major part in identifying the clearest genetic link yet to obesity and three new genes linked to type 2 diabetes, published in April, in advance of the main study.
It has also found a major gene region on chromosome 9 identified by independent studies on coronary heart disease.
The consortium is continuing its work, searching as well for the genetic factors behind tuberculosis, breast cancer, autoimmune thyroid disease, multiple sclerosis and ankylosing spondylitis, a form of arthritis also known as Bechterew's disease.
The results are expected later this year.
