Advances in technology have helped harness the power of genomic sequencing, offering new hope in the fight against genetic diseases. Katie Hampson reports.
What was once a pipe dream to early genetics researchers is now a reality as the genomic age brings new ways to detect and treat disease, and offers families with devastating inherited illnesses a helping hand against fate.
“We humans have never known more about our genetics than now,” says Professor Nigel Laing, an internationally respected genetics expert from Perth’s Harry Perkins Institute of Medical Research.
“It is all about giving information to people that they can use to make decisions with.”
The complex science of genomics isn’t exactly sexy stuff but genetics experts say the benefits to medicine, in particular, have the potential to be huge.
Already, Australian scientists have been relying heavily on genomic sequencing to trace infection outbreaks and, more recently, to understand how COVID-19 is spread in an effort to contain the virus.
“Sequencing the genome of viruses allow us to quickly identify the emergence of new strains,” explains Timo Lassmann, head of the genetics and rare diseases program at Telethon Kids Institute.
Other powerful information that has emerged from sequencing concerns recessive genes for certain diseases.
Most of us are carriers of mutations that are harmless. But Professor Laing says that this can change if we start a family with a partner who has a mutation in the same gene.
Now, couples can undergo genomic sequencing, which he says will identify if they have recessive genes for certain diseases, as well as their risk of having a child affected by a genetic disease. “This means couples no longer have to find out they are at risk of having a child with a recessive disease by having an affected child — they will be informed beforehand,” he explains.
All this is possible because scientists are given a comprehensive picture of a person’s genetic information when they sequence their genes.
Professor Laing says exciting discoveries about which genes are responsible for certain life-limiting rare or undiagnosed disorders are occurring more and more, thanks to the sophistication of today’s sequencing technology.
Research suggests rare conditions affect one in 50 Australians, he says.
“The genome contains the complete set of instructions to build a human being,” Professor Lassmann says. “Understanding what is written in the genome, and how the information is read and used, is highly relevant to understanding human disease and health.”
What is genome sequencing?
When many people talk about their DNA, what they are really referring to is their genome.
Each of us has a genome made up of more than 3 billion letters of DNA, found in nearly every cell in the body, and errors can trigger a vast array of disorders.
The first whole human genome to be sequenced began in 1990 and took 13 years.
It was not without controversy — and not every promise has materialised — but it produced some great strides in medicine.
And, thanks to technological advances, it can now be done in a day for a fraction of the cost, leading to an explosion in genetic research.
Professor Laing says genomic sequencing has already offered tremendous benefits to many people.
For example, scientists have used sequencing to hunt for genes linked to different types of disease, such as breast cancer, and to learn more about inherited disorders, including Huntington’s disease and cystic fibrosis. Families can then find out if they might pass the conditions on to the next generation.
Professor Laing, who has been involved in the discovery of more than 30 disease genes, says that when a diagnosis can be made immediately, it transforms the lives of families.
Take Duchenne muscular dystrophy. This life-limiting condition, which mainly affects young boys, causes every muscle in the body, including the heart, to deteriorate.
One of the problems with DMD is that the early signs are often vague and confusing, which means children are put through a battery of tests in the first years of their life as doctors try their best to work out the cause. These tests can be uncomfortable, invasive, costly and will not necessarily be effective.
Now, thanks to genomic sequencing, Professor Laing says this condition can be pinpointed quickly and some boys with it can now be treated immediately.
“The great thing about genetic testing is that now, for a large number of diseases, the first test a clinician will order is a genetic test and that can get the answer and save a whole lot of other different tests,” he explains.
“Furthermore, when we do a genetic test, we find the variant and that can lead to switching which medication the patient is on from something that isn’t going to work to something that is going to work and that is just joyful.”
The hunt for disease genes
Australia has had a long history of excellence in genetics research and our scientists continue to help discover new disease genes and world-first treatments.
A team of scientists, led by Perth professors Steve Wilton and Sue Fletcher, discovered the first treatment in the world to drastically improve the health of many young people with DMD.
What’s more, Dr David Chandler’s Perth research was crucial in helping to discover a new disease gene responsible for a condition that causes facial deformity. The condition can be devastating, with some babies needing breathing support and a tracheostomy, and the deformity often continues to worsen as the child grows.
One WA family has 12 members who are affected. However, a breakthrough like this meant they finally had the answers they longed for, and so did other families living with the same condition in other parts of the world, including in the US. For the first time, those families are also able to find out if they will pass the condition on to the next generation and now have reproductive choices.
Professor Laing, who jointly supervised Dr Chandler’s research, says hunting for disease genes is like putting together an international jigsaw puzzle.
For a start, DNA from families across the globe needs to be cross-referenced.
And, back when Dr Chandler started hunting for this disease gene some 20 years ago, he could only take his research so far because the technology at the time was limited.
The latest genetic sequencing technology provides scientists with a goldmine of information, which can help researchers achieve the kind of eureka moment experienced by Dr Chandler and the US team of scientists he collaborated with.
“In some ways, I keep feeling it is the people who have invented the new technologies that deserve all the credit here,” Professor Laing says. “Because before the next-generation sequencing came on board, it was just not financially possible to do all the good as a researcher that you would like to do.”
He says as sequencing has become easier and cheaper to do, more diseases have opened up.
Professor Lassmann agrees the field of genomics is full of promise, adding: “I can see the potential across many diseases and (more) people will benefit from genetic screening when treatments and strategies for disease management become available for the majority of possible diseases.”
How genome sequencing has revolutionised healthcare:
Genome sequencing is used in many contexts, says Telethon Kids Institute Professor Timo Lassmann, including for finding the cause for rare and undiagnosed diseases and in cancer. Broadly speaking, however, genome sequencing can currently be used for:
Screening: Detecting conditions and risk factors early before disease occurs, allowing for early intervention and changes in lifestyle decisions.
Diagnosis: Identifying the exact cause of a disease.
Treatment: Identifying the most effective treatment option, thus minimising adverse side-effects while improving patient outcomes.
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