A Tiny Mutation That Leads to Diabetes

Scientists found a tiny mutation on a key gene that could potentially lead to type 1 diabetes, rheumatoid arthritis, lupus and celiac disease and many autoimmune diseases.

The interleukin-21 protein has been associated with the development of type 1 diabetes in mice. Scientists from the Garvan Institute in Sydney, Australia discovered that mice carrying the mutation spontaneously developed type 1 diabetes. When the mice DNA were sequenced they found a mutation, only two base pairs of DNA long, on the promoter region of IL-21 gene.

Dr Cecile King, PhD student Helen McGuire and their colleagues then inserted the mutated DNA segment into a healthy IL-21 gene and observed that more IL-21 molecules were produced. When the gene segment was removed, production of the IL-21 slowed down.

“Our next step will be to analyze the IL-21 promoter region in humans with Type 1 diabetes to see if there’s an analogous defect,” said King. “If there is, then it becomes a predictive marker.”