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Junk DNA' could be key to treating diseases

Among the many mysteries of human biology is why complex diseases like diabetes, high blood pressure and psychiatric disorders are so difficult to predict and, often, to treat. An equally perplexing puzzle is why one individual gets a disease like cancer or depression, while an identical twin remains perfectly healthy.

Medical researchers at the Australian National University have discovered how genetic material previously referred to as so-called 'junk DNA' could help treat auto-immune diseases.

Now scientists have discovered a vital clue to unraveling these riddles. The human genome is packed with at least four million gene switches that reside in bits of DNA that once were dismissed as “junk” but that turn out to play critical roles in controlling how cells, organs and other tissues behave. The discovery, considered a major medical and scientific breakthrough, has enormous implications for human health because many complex diseases appear to be caused by tiny changes in hundreds of gene switches.

The findings, which are the fruit of an immense federal project involving 440 scientists from 32 laboratories around the world, will have immediate applications for understanding how alterations in the non-gene parts of DNA contribute to human diseases, which may in turn lead to new drugs. They can also help explain how the environment can affect disease risk. In the case of identical twins, small changes in environmental exposure can slightly alter gene switches, with the result that one twin gets a disease and the other does not.

As scientists delved into the “junk” — parts of the DNA that are not actual genes containing instructions for proteins — they discovered a complex system that controls genes. At least 80 percent of this DNA is active and needed. The result of the work is an annotated road map of much of this DNA, noting what it is doing and how. It includes the system of switches that, acting like dimmer switches for lights, control which genes are used in a cell and when they are used, and determine, for instance, whether a cell becomes a liver cell or a neuron.

One in eight Australians suffers from auto-immune diseases like type 1 diabetes or lupus.

Senior medical research fellow Carola Vinuesa says the discovery could change the way patients are treated.

"We might have treatments that actually hopefully might actually cure disease rather than just treating some symptoms," she said.

"We might be able to prevent diseases from progressing."

Dr Vinuesa says the research could lead to more specific therapies.

"At the moment treatments are going to knock off the whole immune system and that's the current treatments like using high doses of steroids or the strong drugs we use to treat lupus which is very non-specific," she said.

"So hopefully using this more targeted treatments they will be able to treat the diseases in a way that they suffer less from the side effects."

Professor Chris Goodnow says it could be years till treatment stemming from the research is available.

"This is a major advance but in terms of 'here's something that can go in the bottle' that we know is safe and effective, the shortest you can do that from discovery to is rarely less than 10 years," he said.

"It's the only way to work well and work safely in the translation phase."