Common complex diseases like diabetes, heart disease and cancer cannot be attributed to a single genetic cause. The more likely suspects are multiple gene variants that may have only small or slight effects on their own. These variants at unknown locations on the genome interact in as yet undetermined ways with environmental triggers.
To sort them out, the massive study reviewed 2,000 cases each for seven complex human diseases: bipolar disorder, coronary artery disease, Crohn's disease, hypertension, rheumatoid arthritis and type 1 and 2 diabetes.
The researchers also showed that the same gene variants influenced multiple autoimmune diseases. The study confirmed existing associations at previously identified gene locations, as well as several new ones in previously unsuspected areas.
More: To read an abstract of this paper on PubMed, a medical database, click here.