Australian medical researchers have identified genetic links to 16 diseases, including cancers, Alzheimer's disease and Parkinson's disease, after analysing the complete genomes of 2,000 Australians across 28 types of immune cells. The work, led by scientists at the Sydney-based Garvan Institute of Medical Research and their collaborators, is being described as laying the "building blocks" for a new generation of targeted drug therapies.
What the genetic study found
The research, spanning three linked studies, recorded each participant's full genome and measured gene activity across 28 distinct immune cell types. From that analysis, researchers identified 1,500 genes linked to 16 different diseases, covering autoimmune conditions, inflammatory diseases and cancers.
Professor Joseph Powell, director of Garvan's Translational Genomics program and also affiliated with UNSW's Institute for Genomics and Health, said the team examined how DNA variations influence the activity of genes. They identified 21,000 genes and 180,000 DNA positions that function like a dimmer switch, controlling how actively a gene operates.
"This gives us the ability to identify how these DNA spots are controlling the activity of genes and then link that to disease," Powell said.
The researchers also found DNA that effectively switched genetic activity off entirely, leading to the identification of an additional 350 disease-specific processes operating as a distinct on-off switch mechanism. Powell noted the distinction matters for treatment development: targeting a dimmer switch requires a fundamentally different therapeutic approach than targeting an on-off switch.
Digging into genetic 'junk' across five million cells
One of the more striking aspects of the research involved re-examining what scientists have long dismissed as genetic junk. Hope Tanudisastro, a junior medical officer and postdoctoral researcher at Garvan's Centre for Population Genomics and the Murdoch Children's Research Institute, said the team specifically investigated DNA stutters, known as tandem repeats, which are sequences within a person's DNA that repeat themselves.
"A common theme in science is that we always have to challenge assumptions. We always have to look in places that have been understudied or overlooked," Tanudisastro said.
She described the difficulty of reading these stutters: "It's like trying to count identical beads on a string where you can only see a few at a time. At some point, you lose track." Because of that complexity, most previous genetic studies set them aside entirely.
The team pushed past that barrier, measuring repeats across the whole genome and tracking their effects in more than five million individual immune cells. They found over 69,000 repeat switches influencing gene activity in the immune system, and identified DNA repeats in more than 200 genes linked to conditions including asthma, Crohn's disease, breast and prostate cancer, high cholesterol and anaemia.
Tanudisastro said the findings showed how changes in DNA and gene activity within specific immune cell subtypes can signal when a disease is active, and that this detail could now inform the development of far more precise drug treatments.
Why the findings matter for Australians
Researchers emphasised the urgency of the work given Australia's ageing population. Many of the conditions linked in the study, including asthma, Crohn's disease and various cancers, are common chronic illnesses whose prevalence is expected to grow.
"These are common chronic conditions, and as our population ages, more Australians will be diagnosed with them, which means that better and more targeted therapies are all the more urgent to be discovered," Tanudisastro said.
The broader significance lies in precision. Rather than treatments aimed at a disease in general terms, understanding which immune cell subtypes are involved, and whether the underlying genetic mechanism is a switch or a dial, opens the door to therapies designed to act at exactly the right point. Researchers say the dataset and discoveries now provide the foundational building blocks to pursue that kind of targeted medicine.
