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Why You Should Get Your DNA Sequenced After You Die
Why You Should Get Your DNA Sequenced After You Die
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Sous-titres (170)
0:00
We all know we’re going to die eventually.
0:03
Sorry. This is gonna be a cheery one.
0:05
But sometimes, in rare and devastating cases, death comes out of nowhere –
0:10
out of a clear blue sky, with no warning, in people who seemed totally healthy.
0:14
Autopsies are a go-to method for puzzling out unexplained causes of death,
0:19
but they don’t always clear up the big picture of what happened in the body
0:22
as much as we’d like.
0:23
Fortunately, with modern scientific tools, we can zoom in closer,
0:27
with genetic sequencing to search for clues about what happened.
0:30
Yes, you heard me right, getting your DNA sequenced
0:33
can still be useful after you’ve passed away.
0:36
To help us along in this video,
0:38
we’ll refer to a fictional example patient who we’ll call Jay Doe,
0:42
to visualize when and why we might want to do this.
0:45
[intro
0:49
What happens when we die? To quote Keanu Reeves,
0:52
the ones who love us will miss us.
0:54
They also may want to know what happened.
0:56
Forensic autopsies are ordered in the case of suspicious circumstances or a suspected crime,
1:01
whereas medical autopsies help to clarify the cause of death
1:04
in order to give the family closure.
1:06
Depending on the reason for the autopsy,
1:08
the procedure can include x-rays, incisions,
1:10
and taking samples of the organs,
1:12
all to look for any signs of what caused the death.
1:15
Unfortunately, not every autopsy ends up with a neat explanation.
1:19
Our example individual, Jay Doe,
1:21
was an adult under 45 with no known health risks.
1:25
There was no forensic autopsy,
1:27
since there was no reason to suspect foul play.
1:29
A medical autopsy offered no clear explanation for their death.
1:33
Procedures like this that conclude without finding a clear cause of death
1:36
are classified as sudden unexplained deaths, or SUDs.
1:40
SUD is an umbrella term that covers various causes of unexpected mortality,
1:46
including Sudden Unexpected Infant Death and Sudden Cardiac Deaths.
1:50
And In case your health anxiety needs to hear it, as is mine,
1:54
these are very rare, affecting around 11,000 people in the United States
1:59
under 45 every year.
2:01
That’s out of a population of nearly 200 million people under 45.
2:05
Even though we’ve been doing autopsies for thousands of years,
2:08
the result can still end up inconclusive.
2:11
And for autopsies done on young people with sudden death,
2:13
up to a third might end up without a definitive result.
2:17
But around the turn of the 21st century,
2:19
genetic sequencing gave researchers a new angle t
2:22
o work on explaining those sudden, unexplained deaths.
2:25
Enter the molecular autopsy.
2:28
This procedure can give valuable information to not just medical examiners,
2:32
but also regular folks like the Doe family.
2:34
We’ll learn what that is right after this quick message!
2:38
This SciShow video is supported by Brilliant,
2:40
the online learning platform for math, science,
2:40
and engineering students from grade 5 through undergrad.
2:40
Brilliant’s view is that AI is supposed to be making us smarter.
2:44
But in many people’s educational journeys,
2:46
it seems to be doing the opposite;
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giving them answers that might not even be right without encouraging critical thinking.
2:54
Brilliant’s new tutor, Koji, is their answer to that problem.
2:57
Koji never gives away the answer.
2:59
Instead, Koji will ask questions and guide students to find the answer themselves.
3:04
To get started with Brilliant’s tutor for free, click the link below or scan the QR code.
3:09
You can upgrade to Premium to unlock all courses.
3:11
And right now, SciShow viewers can save 20% off an annual subscription
3:16
at brilliant.org/scishow
3:19
DNA sequencing has been a tool of molecular biologists since the 1970s,
3:24
but it wasn’t until 1999 that scientists started using it in post-mortem investigations.
3:30
These investigations,
3:31
called postmortem genetic tests,
3:33
or informally, molecular autopsies,
3:36
involve sequencing the DNA of the deceased to look
3:38
for genetic clues that could point to the cause of death.
3:41
More specifically, scientists use a technique called whole exome sequencing
3:46
to read protein-coding regions of the DNA
3:48
from the deceased person’s blood and tissue samples.
3:51
The scientists then look through the genetic code and categorize any mutations they find
3:56
based on how likely that mutation is to have been the cause of death.
4:00
Molecular autopsies are done more often on young people,
4:03
as their cause of death is more likely to be unclear.
4:06
Especially in the case of certain sudden cardiac deaths,
4:10
the death may be the first and only sign of a rare mutation.
4:13
For example, long QT syndrome happens when the heart takes
4:16
too long to reset itself in between beats,
4:19
which leads to a super fast, irregular heartbeat.
4:21
Short QT syndrome is the opposite, where the reset time is too short.
4:26
These conditions can lead to an arrhythmia,
4:28
where your heartbeat is irregular or inconsistent.
4:31
This can be harmless, but it can also be life-threatening,
4:33
and sometimes people don't show any symptoms until too late.
4:36
Plus, while both of these are rare diseases,
4:39
short QT is so rare that it was only first described in the year 2000,
4:44
and we’re not totally sure how many people actually have it.
4:47
So if someone passed away because of short QT,
4:50
doctors and medical examiners might not think to look for it.
4:53
Fortunately, we do know some of the mutations that cause those problems,
4:57
which we can find by genetic sequencing.
4:59
Molecular autopsies have been especially helpful in identifying genetic defects
5:04
that affect the electrical signalling in the heart,
5:06
including long and short QT syndromes,
5:08
because electrical defects can’t be seen in a physical examination.
5:13
There are five genes associated with long QT that researchers can look for,
5:17
with about 60 locations in the genome to scope out during a molecular autopsy.
5:21
And some of those genes may also be involved in short QT syndrome.
5:25
So let’s say that Jay Doe’s molecular autopsy revealed
5:28
that they had a mutation associated with long QT syndrome.
5:31
There’s plenty of reason why we’d want to know that, even after death.
5:34
While these autopsies unfortunately cannot change the fate of the deceased,
5:38
identifying those mutations could help other people get checked
5:42
and informed of any possible prevention options,
5:44
including living members of the Doe family.
5:46
By finding out if they have any of the mutations associated with sudden death,
5:50
people can be advised to avoid certain triggers
5:53
and be given preemptive treatments like medications or an implanted heart monitor.
5:58
So, given all of this life-saving information that we can get from a molecular autopsy,
6:02
it might seem odd that this procedure isn’t performed universally in cases of SUD.
6:07
Well, first of all, genetics can’t always tell the whole story.
6:10
As always, the more data, the better,
6:13
and with this relatively new method,
6:14
there is still plenty we don’t know.
6:16
One 2023 review reported that molecular autopsies
6:19
find a possible cause of death just 25% of the time.
6:23
That may at least partially be because diagnostic tools
6:26
for molecular autopsies aren’t fully standardized.
6:29
Even if the autopsy finds a promising explanatory mutation,
6:32
it’s important to confirm that the variant would actually cause the death.
6:36
There are some instances where clinical guidelines
6:38
recommend a molecular autopsy,
6:40
especially in cardiac cases,
6:42
but not having a standardized procedure is actually a pretty big problem.
6:46
Science is all about being able to repeat your findings,
6:49
so having a common method across the field is crucial.
6:52
And because it’s not standard,
6:53
not every medical examiner is collecting
6:56
and preserving the blood and tissue samples
6:58
that you need to even perform the molecular autopsy in the first place.
7:01
Plus, even though molecular autopsies are becoming more affordable,
7:05
especially with genetic sequencing getting ever-cheaper,
7:08
it’s still not nothing –
7:09
at least a few hundred US dollars, up to a few thousand.
7:13
Medicare stopped paying for autopsies in 1986,
7:17
and doctors don’t really want to ask a grieving family to pay for an autopsy simply
7:22
in the interest of the greater scientific good.
7:29
Finally, we have to consider the potential harms of conducting a molecular autopsy,
7:34
especially for the surviving family members.
7:36
Medical examiners aren’t always required to obtain informed consent
7:39
from the family of the deceased.
7:41
And one reason this is a problem is that autopsy reports can be made public,
7:46
which could put the family’s privacy at risk by revealing their genetic information.
7:52
they should be communicated to the immediate family of the deceased thoughtfully
7:56
and with actionable follow-up.
7:58
In the case of negative results,
7:59
the family should be informed of the limits we’ve already talked about –
8:02
that molecular autopsy can’t always find the answer.
8:05
And for positive results, immediate family members
8:08
should be given access to genetic counseling,
8:11
where a healthcare professional can walk them through their personal risk,
8:14
how to manage it physically and emotionally,
8:17
and options about informing the rest of the family.
8:19
In the case of heart conditions like long QT syndrome,
8:22
this could look like regular cardiac check-ups,
8:24
prescribing certain medications, or lifestyle changes.
8:27
A genetic counselor can also help you decide if
8:29
you want to get genetic testing for certain mutations yourself.
8:32
If you’re worried, talk to your doctor
8:35
and they can help you figure out what risk management plan would make the most sense for you.
8:39
With more research,
8:40
we can work towards understanding the causes of sudden unexplained deaths.
8:44
Advances in post-mortem gene sequencing
8:46
can help out regular folks like the Doe family,
8:49
and even possibly prevent sudden deaths like Jay Doe’s in the first place.
8:53
[ OUTRO ]
