SMART THINKER
The relatively new field of genetic pathology involves studying DNA from human blood and tissue to improve – or even save – lives.
Genetic pathologist Dr Melody Caramins follows the DNA clues.
If you’ve ever watched TV shows such as Silent Witness, Bones or Midsomer Murders, you’ll be familiar with forensic pathologists. In these television dramas and many like them, the pathologists work to determine someone’s cause of death by examining their corpse.
However, not all pathologists work with dead bodies. There are many different types of pathologists – the newest field being genetic pathology. As the name implies, genetic pathologists diagnose genetic diseases by examining samples – in their case, from live specimens.
Dr Melody Caramins was the first person in Australia to graduate as a specialist genetic pathologist in 2006. Having grown up with a mother who was an obstetrician-turned-fertility specialist, she was in love with science even as a kid.
“Mum always had anatomical models around the house and I had a real fascination with the workings of the human body – I just always found it really interesting,” she says. “Medicine was something I had always wanted to do ... to help people.” After undertaking her five-year undergraduate medical degree, she spent a further four years studying to become a cardiothoracic surgeon before deciding heart surgery was not for her.
“It’s an all-consuming job. There are not many females in the field and it’s not the kind of job you can do part-time…not that I work part-time now anyway!” she laughs.
“As a junior doctor and intern in the first couple of years, it was pretty stressful – in terms of the hours and the culture of how junior doctors are treated. You’re encouraged to grin and bear it; anything else is weakness.
“I saw bullying happening around me but I was lucky to work with some incredible surgeons who took me under their wing and taught me a lot of skills. Perhaps because I was a no-nonsense, straight-up, direct type of person, I wasn’t directly affected by it.”
Regardless, Dr Caramins became increasingly interested in the diagnostic side of medicine and decided to switch to pathology, necessitating another five years of training, after which she did a PhD in the genetics of platelet count.
At the same time as she was studying genetic pathology, the Human Genome Project was completed (1990-2003), providing scientists with a better understanding of the functions of genes and proteins. “Technological advances from that allowed genetic pathology to become its own field as we got an increase in knowledge of how genes contribute to human disease,” says Dr Caramins
Today, she is the national director of genetics at Healius Ltd. The clinical side of her job broadly entails studying DNA extracted from blood (and also sometimes from tissue) to diagnose genetic diseases such as cystic fibrosis, Down syndrome and haemophilia.
“Genetic pathologists examine changes in the DNA to see how that contributes to disease in an individual,” she explains. “Those changes are not always inherited – they might be acquired, like in a tumour, or a chromosome change that occurs in particular types of leukaemia. Sometimes what we see can also determine the treatment.”
As well as children and adults, Dr Caramins and her colleagues also study cell-free DNA, a common application of which is studying the DNA of a foetus contained in the blood of its mother to determine if there are any chromosomal abnormalities. The tiny fragments of DNA need to be multiplied millions of times in order to be read. Genetic pathologists tend to have little contact with patients – rather they advise other doctors on their findings to help inform a diagnosis or treatment. As Dr Caramins says, they are “the doctor’s doctor”. However, she never forgets there is a living person connected to every sample she diagnoses.
“We treat every sample like it’s a potentially life-changing event for the person at the other end. If you’re dealing with whether or not you have a diagnosis of something like cancer or Down syndrome, I’m acutely aware of the person at the other end. I’ve always wanted to improve things for patients – that’s the reason I did medicine.”
The results of some tests may be evident within a couple of days; some more complicated diagnoses might take 2-3 weeks. “With a simple test, we would get the sample, extract the DNA, amplify it through PCR then detect the specific mutations. Then you would report and interpret that.
“With more challenging samples you always amplify the DNA. You would sequence possibly thousands of genes and the variants in them, then you would compare those with a reference (a normal sequence) so you can pick up the differences and try to interpret all the thousands of variations. There’s a thrill to be had in giving an answer quickly. But the longer study is more like unravelling a detective story.”
For Dr Caramins, no two days are alike. The best thing about the job is the variety and the dynamism, she says. “The landscape is always changing due to the advances in knowledge and technology and you’re also having to be aware of the ethical issues, like privacy and the impact a genetic result can have for other family members.”
“WE TREAT EVERY SAMPLE LIKE IT’S A LIFE-CHANGING EVENT FOR THE PERSON AT THE OTHER END.”