Victoria Gray has sickle
cell disease. She is the first person in the United States to be treated with a
new medical therapy using an enzyme complex called CRISPR.
Victoria is a true
pioneer. If this treatment works for her, it could open the way to the
treatment of hundreds or even thousands of genetic diseases affecting millions of
people around the world.
Sickle cell disease is a
genetic disease that affects over 100,000 people in the United States and
millions of people worldwide. In sickle cell disease, there is a genetic
mutation in one of the proteins that is inside red blood cells. This protein
helps to hold and deliver oxygen throughout the body, the primary function of
our blood. It also helps to give our red blood cells their standard round
The defective protein
(called hemoglobin) makes the red blood cells have a strange, non-round shape,
like a crescent moon. This crescent moon shape is like that of a farm tool
called a “sickle,” hence the name “sickle cell” disease.
Everyone has two genes
that make hemoglobin—one from each parent. If a person has one good gene and
one bad gene, they are said to have “sickle cell trait.” If they have two bad
genes, they will have sickle cell disease, which is also called sickle cell
If someone has sickle
cell trait, they rarely have problems. If two people have the trait, their
children will have the disease. In fact, having sickle cell trait, where a few
red blood cells have sickle shapes but not enough to cause problems, is an
advantage in areas with malaria.
Sickle cell trait
prevents infectious organisms from infecting red blood cells. Malaria can be a
big problem in some regions of Africa and is probably why the abnormal gene has
survived throughout history.
When red blood cells
become misshapen, especially in times of stress or low oxygen, they can
rupture (causing anemia), become sticky, and plug blood vessels. When this
happens, all organs downstream can be damaged.
The pain can be
excruciating. It can also cause strokes and heart attacks, non-healing painful
skin ulcers, and death from organ failure. Many people with sickle cell anemia
live shortened lives. So you see, sickle cell disease is a terrible disease to
How CRISPR works
“crisper”) is one of the most significant advances in medicine ever seen. CRISPR
was first discovered in bacteria as part of a bacterial immune system that cut
up DNA of viruses that were attempting to infect DNA of bacteria.
The CRISPR complex acts
like a scalpel on DNA. In other cells, it can be modified and directed to cut
and repair defective DNA, like the faulty DNA that makes the abnormal protein
that produces sickle cell disease.
That is precisely what
scientists did for Victoria Gray. They took the stem cells that make her red blood
cells and used CRISPR to repair her defective DNA. They then put the corrected
stem cells back inside her, where they would go to her bone marrow (where those
blood cells normally reside) and, hopefully, they will start producing healthy
red blood cells. This amazing process can potentially “cure” her sickle cell
These are exciting times
to see CRISPR move from the research lab into the arena of medicines that can
be used to help people and possibly cure diseases. Several companies are
leading the way in CRISPR medicine development, and they are currently looking
at other blood diseases, eye diseases that cause blindness, and certain
Therapeutics and Vertex Pharmaceuticals and Bluebird Bio (Europe) are leading
the charge for novel gene-editing therapies. CRISPR holds the promise to
treat and cure thousands of diseases in the future.
The hope is that it will
give Victoria enough healthy red blood cells to prevent her from developing
many of the complications associated with sickle cell disease and that she can
live a long and prosperous life. The jury is still out, and hopefully we will
see some fantastic results for her in the upcoming months.
This ingenious treatment
for sickle cell disease may open the door to a new future in medicine and