Genes for Several Common Diseases
A study of seven illnesses, including diabetes and cardiovascular disease, identifies possible culprits
SOURCE: “Genome-Wide Association Study of 14,000 Cases of Seven Common Diseases and 3,000 Shared Controls”
The Wellcome Trust Case Control Consortium
Nature 447: 661-678
RESULTS: A massive genetic study carried out in the United Kingdom pinpointed 24 genetic markers that increase risk for seven common illnesses. The study found one marker for bipolar disorder, one for coronary-artery disease, nine for Crohn’s disease, three for rheumatoid arthritis, seven for type 1 diabetes, and three for type 2 diabetes.
WHY IT MATTERS: Unlike rare diseases such as Huntington’s, where a single genetic variation guarantees that a carrier will be afflicted, common diseases are triggered by a complex array of factors, including multiple genes each exerting a modest effect. The new study illustrates the success of a new approach to gene hunting known as genome-wide association, in which scientists scour the entire genome for disease-specific variations. The vast scope of such studies–in this case, almost 10 billion pieces of DNA–provides enough statistical power for researchers to find genetic variations that raise the risk of disease by a modest amount.
METHODS: The scientists used gene chips to analyze 500,000 genetic markers in each of 17,000 people. To identify genetic variations linked to specific diseases, they compared the DNA of 2,000 patients who had one of the diseases with that of 3,000 healthy controls.
NEXT STEPS: The researchers will try to confirm additional genetic variations hinted at in the current study by analyzing genomic information from larger numbers of people.