In the midst of the pandemic and protests and political mayhem, the grim news can be overwhelming. But there’s wonderful news, too. Remember the gene-editing technique, CRISPR? A year after gene-editing, a woman with severe sickle cell disease feels great. This success signals hope of a cure for Sickle Cell disease.
Sickle Cell Disease
According to the Centers for Disease Control, Sickle Cell Disease (SCD) is a group of inherited red blood cell disorders.
A healthy red blood cell is round. It travels through our blood vessels, even the tiny capillaries, and delivers oxygen to all parts of the body. When a person has SCD, their red blood cells become hard and sticky and shaped like a farm tool called the sickle.
These abnormal cells get stuck in small blood vessels. This clogs blood flow. It can cause mild-to-severe pain and many serious problems like strokes. These cells also die early, causing anemia.
There are three common types of Sickle Cell and three rare types. Some people carry the trait (they have half the genetic material that causes the disease). If two people with the trait have a child, they have a 50% chance of passing on the trait and a 1-in-4 chance their child will have the disease.
SCD occurs among about 1 out of every 365 Black or African-American births. SCD occurs among about 1 out of every 16,300 Hispanic-American births. About 1 in 13 Black or African-American babies is born with sickle cell trait (SCT). Historically, mortality in the first three years was 38%. This has improved, but premature death remains a risk of this disease.
The first symptoms of the disease occur during the fifth to twelfth month of life. The only cure for SCD is bone marrow or stem cell transplant. Both procedures have risks and complications. It’s not an option for everyone.
The CRISPR Treatment
In 2019, at least two patients with severe SCD received an injection of CTX001 in a trial.
CTX001, made using the gene-editing tool, CRISPR-Cas9 changed the patients’ blood cell so they produce high levels of fetal hemoglobin.
Fetal hemoglobin is present before birth and drops to trace amounts about six months after birth as hemoglobin A (adult hemoglobin) production takes over. Fetal hemoglobin inhibits sickling.
One Year Out
Victoria Gray, 34, is the first patient to have received CTX001. NPR reported that one year after the injection she is thriving. The treatment has alleviated nearly all her complications of SCD.
She’s grateful and expresses that the treatment came just in time. She’s not needed to go to the hospital at a time when the pandemic makes that a scary place to be and while the National Guard deployed her husband.
Scientists are optimistic that this experiment is a success.
I could not find out about the second patient who received the treatment, which suggests the experiment hasn’t been 100% successful. But it gives us hope of a cure for Sickle Cell Disease. And as a nurse who has witnessed the terrible effects of SCD, I am rejoicing alongside the 100,000+ Americans who suffer from this disease. May the future bring even better news and not just for SCD but for other dreadful genetic diseases.