To the beat of one's heart
At the end of a fascinating, if complex, lecture in my early
years of Medical School, the lecturer had one slide that made me giggle quietly
to myself. “Social Media,” he said, “is apparently all the rage with you young
people. So I’ve got a twitter account, and a Facebook page, and a website.
Please feel free to contact me!” Being a rather avid user of Twitter, I did
just that. And, for the past two years, we’ve kept in contact via social media.
Prof is insistent that I consider cardiology, the specialty that …err…beats
with his heart, as one that could capture my own.
It was on an unseasonably hot November day in the middle of
my exam study period that we met for the first time. I wanted to learn more
about the Prof’s work. And I wanted to share it on this new-fangled social
media thing.
I arrived at his office ten minutes early – hot, sweaty and
worried about making a good impression. While I was watching the winning
entries for a science photography competition scroll through on the over-sized
LED TV in the lobby, I heard a voice behind me. “Are you Brooke?” it asked. I
turned around and saw Professor Chris Semsarian, who looked exactly like his
profile picture but a little bit different at the same time. Who looked quite a
bit different close up than he did at the lecture so long ago. “I’m quite
nervous,” he said, “I’ve never met anyone off Twitter before.” Just quietly, I
thought, I was a little bit nervous too. However, my response was upbeat. “It’s
great fun meeting people you’ve gotten to know quite well online,” I countered.
There’s the awkward beginning of the conversation, where you feel decidedly
like small talk is necessary, even though you’ve shared travel recommendations,
family events and study woes. Even though you’ve cheered each other on and
celebrated individual wins. Pretty soon, we were hitting it off. It was almost
as if we were on Twitter, except we had a lot more than 140 characters per
exchange.
As a genetic cardiologist at one of Australia’s most famous
hospitals, and as a consultant who’s constantly in demand at national and
international conferences, I was in for a treat. I wanted to know about the
future of genetic cardiology. It turned out I was in the right place.
As Prof Chris explained, there are over 45 identified
cardiovascular diseases with a genetic basis. Thanks to research and the decreasing
cost of genetic tests, we’ve been able to put together more and more pieces of
the cardiovascular disease puzzle. We have a growing list of conditions with an
identifiable risk factor or cause (depending on whether diseases are autosomal
dominant or recessive or non-Mendelian, single-gene or polygenic). The problem
is that, since genetic therapy was discovered over twenty-five years ago,
there’s been a depressingly unproductive cohort of research in the area. It’s
not for lack of trying – we just haven’t cracked the code yet.
For Prof Chris, this can be devastating.
Imagine being at a football match or a local sporting
competition and seeing a young athlete collapse. For a moment, the crowd is
watching the chase of the ball or the race leaders, and then they notice the
athlete prone on the grass. At first, everyone thinks this poor person has
tripped himself or herself over. But then, they don’t get up. They don’t
respond when someone shakes them and calls their name. And, when the paramedics
arrive, they don’t respond to CPR. It happens occasionally. But for the
families left behind, this rarity is far more devastating than the statistical
population probability.
When tragedies like this happen on the field, it’s often
Prof Chris who gets the phone call. Sometimes the call is from the local news
channel, hoping to find out answers. Sometimes it’s from families wondering if
they or their loved ones are at risk.
Everyone, understandably, wants answers.
It would be easy to jump to a defensive strategy – to
suggest we test everyone for genetic diseases. And we could – but at a great
economic, social and ethical cost. When
would we test people? At birth? At 18? When there’s a family history of
disease? How would a positive genetic test affect future employment prospects
or eligibility for sporting teams, or access to health insurance? If you end up
doing a whole genome test, would you tell someone they have a BRCA1 gene (a
marker that almost certainly guarantees breast cancer in women) found
incidentally on a search for SCN5A (a marker for a channelopathy that is found
in Long QT syndrome, which can be responsible for sudden death)? There are
thousands of questions to be asked…and we don’t yet have sufficient answers.
So what do we do at the moment? Because genetic diseases
generally run in families (though there are sporadic mutations – cancer is a
condition of changed genetics, though these are somatic, meaning from the cell,
rather than inherited), genetic testing can be offered to families with known histories
of genetic disorders. These are
sometimes available at a subsidised cost on private or public health insurance.
Sometimes, they’re only available at a rather pricey figure, because analysing
an entire genome for a specific marker is more expensive than printing out all
of the As, Ts, Gs and Cs that make up your DNA picture.
Solutions can be easier to construct when an answer is more
precisely known. If a disease is monogenetic and known to have full penetrance,
treatments, cures or preventative measures can be taken early. That is, when we
have solutions we can give people. There are, sadly, a number of conditions we
can identify genetically and with close to 100% penetrance but for which we
currently have no cure. If the prognosis
is unknown given the genetic results, it can be very difficult to explain and
deal with statistical probabilities. Does it matter if there is a 5% risk of
you developing a condition if you end up being part of that 5%? And if there’s
a 95% probability of developing a condition, there’s still a 5% chance you will
go through life totally fine. Making decisions on the basis of a genetic test
is complex – for the individual, for the physician and for the surgeon who may
need to perform a prophylactic procedure.
As science progresses, I asked, will we see new solutions
that make these genetic tests more worthwhile? Will we be able to grow new
hearts rather than relying on transplants? Will we be able to build scaffolds
for stem cells to fix massive areas of damage in existing hearts – literally
healing a broken heart? Will we be able to create specific enough drugs that
have few, if any, side effects? And how do we revise our practice of
evidence-based medicine to encompass these developments?
Prof Chris looked at me with sadness in his eyes. Sadly,
growing new hearts are a long way off, given current progress in the field. The
heart is an immensely complex organ, relying on multiple layers of tissue,
varying neural pathways and a gaggle of hormonal messages. It’s more than the
simple pump we’re taught in physiology. And, because of genetic conservation
across organs, many drug targets in the heart will also have targets in other
organs – often with rather deleterious effects. Solutions aren’t as obvious as
you’d think.
So what answers can be given to desperate families on the
other end of the phone? Thankfully, frequent monitoring, pacemakers and
automated internal defibrillators, medications and lifestyle modifications can
significantly reduce the risk of death in many of our genetic cardiovascular
diseases. Genetic testing can be helpful, if not a complete or perfect answer.
Medicine has opened up a Pandora’s box when it comes to our
futures. We now know more than we ever knew before – but we often don’t know the
‘why’ or the ‘what to do next.’ As science attempts to answer many of questions
we find with each new discovery, it will be up to you, to your families and to
society at large to develop guidelines for our next steps.
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