The CRISPR gene-editing technique has been used to treat some hereditary blood disorders, such as sickle cell anemia and β-thalassemia. As published in the journal Science, CRISPR has been applied for the first time to treat β-thalassemia and sickle cell anemia. These patients have mutations in both copies of the gene that produces hemoglobin, so it does not work well and the blood is not properly oxygenated. The technique involves taking blood from the patient and correcting the BCL11A gene responsible for the disorder using CRISPR, before injecting the blood with the corrected abnormality back into the patient. The first patients treated were found to have a sufficient level of fetal hemoglobin, so they no longer have the crises caused by this disease. This is unquestionably an encouraging step in the treatment of one of the most prevalent hereditary blood disorders.