Sickle cell disease (SCD) is a group of inherited red blood cell disorders. The disease is caused by a genetic mutation that produces a defective form of hemoglobin, the protein in red blood cells that carries oxygen. The defective hemoglobin turns red blood cells into deformed, sickle-shaped cells that tend to get stuck in narrow blood vessels, causing excruciating attacks of pain, organ damage and often premature death. Over time, sickle cell disease can lead to complications such as infections, delayed growth, and episodes of pain, called pain crises. And adolescents and adults who have sickle cell disease may also suffer with chronic, ongoing pain.
In late June this year, National Public Radio caught up with Victoria Gray, the first person in the US to get treated for SCD by CRISPR gene editing. Last summer, doctors took out bone marrow cells from Gray's body, edited a gene inside them using CRISPR to turn on the production of fetal hemoglobin, and infused the modified cells back into her system. Fetal hemoglobin is a protein made by fetuses in the womb to get oxygen from their mothers' blood but usually stops being produced shortly after birth. The hope is that recovering production of fetal hemoglobin will balance the defective adult-hemoglobin sickle cells that patients produce.
It has been one year since Gray was treated and she has just been told that the billions of modified cells infused into her system are clearly shown to be helping almost all the complications of SCD. About 46% of the hemoglobin in Gray' s body is still fetal hemoglobin and in 99.7% of her red blood cells the fetal hemoglobin has remained exist. Moreover, more than 81% of the cells contained the intended genetic change needed to produce fetal hemoglobin, suggesting the edited cells were continuing to survive and function in her body.
Reference:
1.Information for Sickle Cell Disease from https://www.nhlbi.nih.gov/health-topics/sickle-cell-disease
2.Rob Stein. A Year In, 1st Patient To Get Gene Editing For Sickle Cell Disease Is Thriving. Jun 23, 2020. Retrieved Jun 24, 2020 from https://www.npr.org/sections/health-shots/2020/06/23/877543610/a-year-in-1st-patient-to-get-gene-editing-for-sickle-cell-disease-is-thriving?utm_medium=RSS&utm_campaign=health
3.Rob Stein. A Young Mississippi Woman's Journey through a Pioneering Gene-Editing Experiment. Dec 25, 2020. Retrieved Dec 30, 2020 from https://www.npr.org/sections/health-shots/2019/12/25/784395525/a-young-mississippi-womans-journey-through-a-pioneering-gene-editing-experiment
