Once rare mitochondrial disease striking generations of families
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Kara Crawley, 18, had a big heart.
Until she died in March from a major stroke caused by mitochondrial disease, which doctors now realise is 100 times more common than they thought even a decade ago, she had wanted to become a doctor like her mother to help others.
Karen Crawley with her children, Samantha, 11, and Braden, 17, in Sydney. Her oldest daughter, Kara, passed away from mitochondrial disease and her son has just been told that he is suffering from the same genetic illness. Photo: Janie Barrett
Around one in 200 people carry a mutation making them vulnerable to some form of disease of the mitochondria, which are often described as the powerhouses of our cells.
If they don’t work, our bodies can’t produce enough energy, and children like Kara – who was healthy until she had severe gastroenteritis at aged three – will fail to thrive.
In the Crawley family, all three children inherited a disease caused by a mutation in the DNA which is only carried down the maternal line. This is the cause of about half of all mitochondrial diseases. The balance are caused by nuclear DNA, genes inherited from one or both parents. Research shows they can, in some cases, be the cause of hearing loss, Parkinson’s and diabetes.
In the months before Kara died from her 20th stroke, the only thing she could do was to sit in her wheelchair with a peg basket balanced in her lap while her mother Karen Crawley, a general practitioner, hung out the washing.
“For Kara, just to sit in a wheelchair and hold the peg basket was equivalent to another kid going overseas on a holiday. She’d say “I am helping Mum’,” said Dr Crawley of Sydney’s Yowie Bay.
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Since mitochondrial DNA was first identified in 1988, more than 300 genes have have been discovered with the potential to cause the disease, said expert David Thorburn, who is the head of mitochondrial research at the Murdoch Children’s Research Institute, located in the Royal Children’s Hospital in Melbourne.
Kara Crawley, who passed away from mitochondrial disease in Sydney. Photo: Janie Barrett
Even 20 years ago, doctors thought it occurred in about one in 20,000 people.
It is only now that families are realising mitochondrial diseases could explain generations of unexplained infant deaths or adults who died prematurely from strokes or diabetes.
Kara Crawley. “She taught us to smile at the smallest of things, and appreciate the quietness of having time together and giving me a cuddle,” Karen Crawley says. Photo: Janie Barrett
“It is not uncommon that we diagnose a child, and look back and discover mum’s brother died from Leigh’s disease [caused by mitochondria] or a child died from an unexplained illness,” he said.
“They are horrible conditions for a family to deal with, and there is a lot of uncertainty. People, children, who appear to be healthy, but then they develop symptoms.”
Kara Crawley, who passed away from mitochondrial disease in Sydney. Photo: Janie Barrett
Not everyone with a mutation will have the disease, but around one child born a week – and one in 2000 Australians – will have a severe case.
As yet, there is no cure. Research has yet to find an effective treatment, other than drugs to reduce symptoms such as seizures.
Karen Crawley completes one of the Bloody Long Walks in Kara’s memory. Photo: Janie Barrett
The outlook is bleak, admitted Professor Thorburn.
To prevent generations from inheriting the disease, the United Kingdom has changed the law to allow women at risk of having a baby with potentially fatal forms of mitochondrial disease to undergo a controversial procedure known as mitochondrial donation.
Unlike nuclear DNA (left), mitochondrial DNA is only inherited from the maternal lineage (right). Kara had mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), which she inherited from her mother.
An Australian campaign was launched last week to allow “three-person babies” but the federal government has indicated it has no immediate plan to change the law to allow it.
In the meantime, Dr Crawley and Professor Thorburn are trying to educate doctors about the disease so that families will avoid the tortuous path to diagnosis that Kara faced.
They are developing an Australian version of new patient care standards developed in the United States.
Like most doctors, Dr Crawley never suspected that mito (as it is called) was the cause when Kara was first unwell. It took five years, many visits to sceptical medical exerts, and trying to piece together a range of puzzling symptoms.
“Between three and eight years of age she put on one kilo. She was clumsy and very hairy. All her baby teeth fell out early, but her adult teeth were coming in. It was always something that wasn’t quite right,” she said.
It wasn’t until Kara went into puberty at the age of seven that an endocrinologist suspected it was something genetic.
Only three weeks later, Kara had what appeared to be another case of gastroenteritis and a major seizure. It was then that an MRI revealed she had an earlier stroke and a new one.
The family discovered she had MELAS (Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes), a common disease caused by the mutation carried down the maternal line.
Her two siblings, Braden, 17, who has moderate symptoms of the disease, and her younger sister Samantha, 11, also inherited the same mutation.
The amount of this mutation varies from egg to egg, and exposure to viral infections such as Kara’s early years, may trigger the illness so that siblings may have very different outcomes.
Like the Crawleys, most families find diagnosis is difficult.
Many are made to feel they are scaremongering. They may wonder if their children are lazy.
For years, Dr Crawley ran a 24-hour, seven-days-a-week mitochondrial help line.
“In every case, families had at some time been referred to a psychiatrist or a psychologist,” she said.
“We are saying put mito on your checklist, treat us seriously, “said Dr Crawley.
An 83-year-old woman called to say she thought she had the disease. Dr Crawley initially suggested that ageing was to blame, but the woman persisted, saying something wasn’t right.
“She told me she was sick of people saying you are 83,” Dr Crawley recalled.
That woman was diagnosed with mitochondrial disease.
“She deserves the dignity of knowing,” said Dr Crawley.
Even though exercise has been shown to provide some protection from the disease, too much can put someone at risk because the body can’t produce enough energy to replace its depleted “battery”.
That’s not stopping Dr Crawley, who has some symptoms of the disease.
To raise awareness of the disease, she is pushing her late daughter’s wheelchair a total of 245 kms to complete every one of the seven Bloody Long Walks of 35kms.
“We are better people [for knowing Kara]. She taught us to smile at the smallest of things, and appreciate the quietness of having time together and giving me a cuddle.”
She hopes greater awareness will lead to more research, and great understanding by the medical profession which could help children, adults and their families.
Info: bloodylongwalk.com.au
Article source: http://watoday.com.au/afl/afl-news/richmond-tigers-have-proven-the-doubters-wrong-with-2017-grand-final-win-20170930-gyry45.html
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