Researchers ID Genes for Some Common Diseases

Mar. 23 -- WEDNESDAY, June 6 (HealthDay News) -- In the largest study to date of the genetics of diseases, researchers say they've substantially increased the number of genes believed to play a role in the development of common illnesses, ranging from bipolar disorder to diabetes.

Many of these genes were found in areas of the human genome not previously thought to be related to the diseases, the researchers said. While much was already known about genetic-based diseases, such as cystic fibrosis, little was known about the genetic components of more common diseases.

"These are like heart disease, schizophrenia, depression and arthritis, where we have known that genetics plays a role, but we haven't been able to pinpoint the genetic factors which are involved," said lead researcher Peter Donnelly, of the Department of Statistics at the University of Oxford in England. "Our study is a new dawn to understanding genetic components of common diseases.

"For most common human disease, despite hundreds of years of research, we know depressingly little about what causes them," added Donnelly, who is also chairman of the Wellcome Trust Case Control Consortium. "The big hope with genetics is to give us a new foothold on a new way to understanding the biology of these diseases."

Donnelly noted that a number of approaches had been tried to identify genes connected to common diseases. "There have been a small number of successes but not as good as we would have hoped," he said.

Now with new technologies, only available in the past two years, researchers have been able to do "gene associations studies," which have made linking genes to diseases possible, Donnelly said.

"It is very clear that these studies work," he said. "As a consequence, our understanding of common human diseases is about to change very substantially."

For the new research, the study authors concentrated on seven diseases and found genetic links for each one. These are bipolar disorder, Crohn's disease, coronary heart disease, hypertension, rheumatoid arthritis, and type 1 and type 2 diabetes.