New gene shows way for autoimmune disease

A new gene suspected to contribute to autoimmune diseases such as type 1 diabetes and lupus has been discovered by ANU immunologists.

The researchers found that a mutation in the gene, which they have named Roquin, causes the body's infection fighters - T-cells - to attack their own tissue; the realisation opening the way to explore treatments that target the mutation.

Studies of the gene are under way in patients with lupus and type 1 diabetes to determine whether the same or similar mutations observed in laboratory mice are present in humans.

The researchers mirrored the spontaneous genetic variation that occurs naturally during population growth by introducing random changes in the mouse genome, generating novel models of autoimmune disease. After identifying signs of lupus, they worked backwards to find the altered gene responsible for the condition. Before this study, the existence and function of Roquin was not known. However, we now know that in the immune system of mammals, the protein Roquin usually suppresses the activity of forbidden T-cells that bind to parts of the body.

According to Professor Christopher Goodnow, the Head of the Immunogenomics Laboratory at JCSMR and Director of the Australian Phenomics Facility, the discovery hinged on identifying a single letter change in the DNA code of Roquin.

According to Professor Goodnow, the characteristics of the Roquin protein suggest that it might repress immune cells by silencing the communication channel between genes and cell functions.

The discovery was part of a research program into autoimmune diseases by the John Curtin School of Medical Research, the Australian Phenomics Facility, the ANU Medical School and Oxford University, Professor Goodnow said.