[♩INTRO]
Last week was a pretty big deal for the future
of medicine.
For the first time ever, researchers injected
someone with tools that would edit his DNA,
hopefully curing his genetic disease.
If it works, it’ll be a huge step toward
treating some of the world’s most debilitating
genetic diseases.
But despite the connections being made in
some places, this isn’t ushering in the
age of designer babies.
On November 13th, a man named Brian Madeux
received billions of carefully-designed, gene-editing
viruses via an IV.
Madeux has Hunter syndrome, which means he’s
missing an essential enzyme for breaking down
certain kinds of large sugar molecules.
Instead, these sugars accumulate in his cells,
causing them to swell, and making his tissues
and organs grow to abnormal sizes.
Hunter syndrome can lead to all sorts of problems,
including less mobility, vision and hearing
loss, brain degeneration, and heart disease.
And like many rare genetic diseases, it has
no cure.
Patients can get enzyme boosts to ease their
symptoms, but they’re incredibly expensive,
and the enzyme levels drop off quickly.
Gene editing — if it works — would be
a much more effective treatment.
The idea is almost exactly what it sounds
like: you take a patient’s genes, and you
edit them, usually with the goal of fixing
a mutation or curing a disease.
Researchers have been trying to cure diseases
this way since 1989, but in the last few years,
gene editing techniques have gotten much more
accurate and reliable.
There are already some approved treatments
that involve taking the patient’s cells
out of their body, modifying their genes,
then putting the cells back in.
With Madeux, researchers are doing something
new: the tools to edit his DNA were injected
directly into his blood to then go modify
cells elsewhere in his body — in this case,
his liver.
While most of the gene editing research you
hear about these days uses a tool called CRISPR,
this treatment uses a system known as zinc-finger
nucleases.
It’s a slightly older method that’s harder
to design and make, but it also has a good
track record.
Zinc-finger nucleases consist of two essential
parts—a DNA-clipping enzyme, and a section
that binds directly with the part of the genome
you want to cut.
To edit genes, scientists design a pair of
these DNA clippers that cut both halves of
the DNA strand.
If the bit of DNA they want to add is designed
to match the sequences at those broken ends,
then when the cells go to repair the break,
they’ll sometimes include the new gene.
For Madeux’s treatment, the blueprints for
these gene-editing tools were packaged in
modified viruses, which, you know, infect
cells — the way that viruses do.
Then, all the team needed to do was put them
in a plain old IV.
If all goes according to plan, Madeux’s
liver will transform into a mini manufacturing
plant for the enzyme he lacks.
According to the researchers, if the gene
gets into 1% of his liver cells successfully,
he’ll make enough of the enzyme to treat
his condition.
But that’s a big if.
Gene therapy trials are known to be risky.
People have died when the viruses used in
other types of gene therapy treatments sent
their immune systems into overdrive.
And that’s not the only potential complication.
Sometimes the introduced genes land in the
wrong spots and cause cancer.
And if the gene is activated in the wrong
cell type, it can cause other issues.
The new treatment is designed to avoid putting
the gene in the wrong place very often, and
there’s a failsafe that’s supposed to
prevent the insert from working in any non-liver
cells.
But there’s always a chance something could
go wrong, and if it does, there’s no going
back.
They won’t be able to un-edit his cells.
That’s the risk—and reward—of what Madeux
signed up for, and it may take several months
before we know whether the experiment succeeded.
Even if things do go smoothly, though, the
therapy isn’t necessarily going to cure
him completely or indefinitely.
This genetic editing should help with most
of the symptoms, but the enzyme probably won’t
be able to cross the specialized barrier that
protects the brain, which means it won’t
be able to prevent brain damage.
It also can’t reverse the damage the disease
has already caused over the past 44 years
of his life.
And the therapy should work for at least several
years, but how long it remains effective depends
on the age and type of cells that incorporate
the new gene.
The ultimate goal, though, isn’t to treat
adults like Madeux and the other volunteers
in this study—it’s to develop a safe enough
protocol to use in children or even infants.
That way, they’d be spared the syndrome’s
worst effects.
And if this treatment works, researchers will
also be a lot closer to developing similar
gene therapies for other types of diseases.
But one thing this research will not get us
closer to is some dystopian future where we’re
genetically engineering our children to have
extra fingers or whatever.
Whenever there’s a new development in gene
therapy, there’s a lot of talk about the
risks of babies with edited genes, or how
to draw the line between editing an embryo’s
genes to eliminate a disease and custom-designing
a person.
And those are real ethical problems that we’ll
need to solve before we start using gene editing
to change someone’s genome before they’re
born.
But research like this, where scientists are
trying to treat a disease in a living person,
is totally different.
The changes to Madeux’s DNA won’t be happening
in any of the cells destined to become sperm,
so there’s no way for him to pass them on.
This is a pretty big leap for gene therapy,
especially if it works without serious complications.
But it’s not designing babies.
Alright, I’ve got an EXCITING ANNOUNCEMENT
for you.
The SciShow team and I were talking about
a common problem that many of us have.
When people ask us what we want for Christmas
or for our birthdays, often, we won't know
what to say and then they’ll get frustrated
and we’ll get frustrated and it’s like
“I just wanted to do a nice thing for you
and you’re being so stubborn!”
But I don’t know!
I don’t care about stuff that much.
But I was thinking, you know, there are a
few things that I would like to get or that
I’ve bought for myself of that people have
gotten me that I loved because I love the
world and the universe and understanding things
and the existence of life and doing experiments
on my proteins -- that kind of thing.
So, we’ve put together a collection of artifacts
of this universe.
We got a limited number of each of these things
and we’ve put up at a store called SciShowFinds.
These SciShow Finds are curated by me, they
are things that I know I would love to get
in my stocking.
It's a very small list, just six cool things
with varying price points.
And I did my best to only include one science
book, It was very hard to pick, but I picked
the one that had the most impact on me of
all the books that I read this year.
It's called "What is Life" and it makes an
extremely compelling case that biology is
like a chemical inevitability.
And, along the way, you learn a whole lot
about chemistry, and it’s great, because
-- you might end up googling things every
once in awhile to make sure you know what
the author’s talking about -- but at the
end of the book, you will understand chemistry
in a whole new way.
We're probably going to add new finds...as
we find them...throughout the year, and the
new ones will replace these old ones, so these
products are only around for a limited time.
You're bound to have friends or family who
would love these Mars Socks, trilobite fossils,
or this Space Shuttle lapel pin.
And, if not, you might want to get them for
yourself or just send that link over to somebody
who’s saying to you, “what do you want
for Christmas?” and it’s like, “Just
anything from this website, Ma.
You’ll be getting me socks that I’ll actually
appreciate this time.”
And know that when you buy from SciShowFinds.com,
or you send that link to somebody else, you
are also supporting SciShow.
So, thank you for doing that.
And I know what you’re thinking, “Can
I get that cool SciShow hoodie at SciShowFinds.com?
You can’t.
You can’t.
This is just for staff.
Sorry.
[♩OUTRO]
