New genetic research sheds light on sudden unexplained death in the young
By Diane Luckow
Informing a grieving family that their child has suddenly died of unexplainable causes is a painful task for all coroners. Yet that’s the sad reality in an estimated 700 pediatric deaths each year in Canada.
But recent SFU alumna Laura Dewar, a former B.C. coroner who graduated from SFU last December with a PhD in biomedical physiology and kinesiology, says her thesis research has revealed some promising clues about the cause of these deaths.
Dewar scaled back her death investigation work in 2011 to instead investigate the potential genetic causes of sudden unexplained death in the young (SUDY).
SUDY refers to cases where an apparently healthy person with no previous diagnosis of a life-threatening disease suddenly dies for no apparent reason. In about one-third of adult SUDY cases (up to age 40 or even 50 years), and in up to 80 per cent of infant SUDY cases, an autopsy fails to reveal a cause of death.
“Nothing shows up in an autopsy, or in ancillary tests such as biochemical analyses or toxicology,” says Dewar who, after 24 years as a coroner, felt she had to find some answers. She had begun to wonder whether a genetic component might be responsible, and decided to return to graduate school to research the possibility.
Working with SFU professor Glen Tibbits, an expert in pediatric cardiac physiology, she concentrated her PhD research on the potential genetic causes of SUDY. One known underlying cause is sudden cardiac arrest due to inherited heart rhythm disorders, such as long QT syndrome. She focussed on finding genetic variants in a number of different genes associated with inherited heart rhythm disorders, but also included genes that no-one had yet examined.
“I did find one particular variant in a gene that has not been previously investigated, and there is now ongoing research at SFU using stem cells to see if it could be a potential cause of SUDY,” she says.
Just as importantly, she also developed some post-mortem guidelines that she hopes coroners and medical examiners will adopt when dealing with SUDY.
“We need to ensure that, in these cases, post-mortem tissue is retained after the autopsy so that future genetic testing can be done,” says Dewar, who is now seeking funding for a post-doctoral position so she can spread the word.
“When a family loses a child and there are no answers, it’s important to ask them to be clinically assessed by experts in SUDY so that the immediate family is not at risk for another tragic death.
“Clinical tests (including genetic testing of both the living and deceased relatives) can unmask the disorder and, in many cases, life-saving treatment can be as simple as a lifestyle change—perhaps taking medication or avoiding high-level sports.”
Some people, she adds, may need an implantable cardioverter-defibrillator, similar to a pacemaker, to prevent their heart from going into a dangerous rhythm.
Dewar graduated at age 54, a time when most people are beginning to think about retirement. But her deep interest in finding answers for families kept her on track.
“The first few years were overwhelming,” she admits, particularly since she had earned her master’s degree in human genetics 30 years earlier.
“I often asked myself, ‘What are you doing? You’re surrounded by students who could be your grandchildren. It was intimidating’.”
Now, she’d like to work with specialized clinics that are investigating inherited heart disorders. She wants to develop policy that would help strengthen the relationship between their work and that of death investigation agencies.
“The peace of mind I’d like someday is knowing that, while we can’t prevent all SUDY deaths, regardless of where a child dies they’ll get the best investigation possible.”
She also wants to educate family physicians and the general public to be aware of the subtle signs of heart rhythm disorders, such as palpitations, chest pain and/or episodes of syncope or near-syncope (fainting and near-fainting).
“When a child says “my heart feels funny” after running up the stairs, it shouldn’t be ignored. It could be a flag for an underlying heart disorder. Treatment, not just for the child’s sake, but for the whole family, can be life-saving.”