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 shape.
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 anemia.
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 have.
How CRISPR works
CRISPR (pronounced “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 disease.
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 cancers.
Currently, CRISPR 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 medical cures.
- “CRISPR: life-changing, world-changing science that will revolutionize medicine” (June 1, 2018)
- “FDA approves first new sickle cell medication in 20 years” (September 20, 2018)
- “Malaria: a disease caused by protozoa carried by mosquitos” (August 16, 2018)
- “The miracles of blood” (September 21, 2017)
- “The miracles of blood – Part II”(September 27, 2017)