Exciting CRISPR-based Sickle Cell Disease Treatment
In our bodies, the instructions from thousands of genes are necessary for accomplishing essential functions that require precise and accurate control even at an extremely small scale. Even the smallest mutations in our genetic code can disrupt these finely tuned operations, resulting in catastrophic and oftentimes irreparable damage throughout the body.
Sickle cell disease (SCD) is a common example of an illness resulting from a small mutation, specifically a point mutation, where a single base pair underwent deletion, incorrect insertion, or is changed altogether. When the gene where this mutation occurs codes for a subunit of hemoglobin, it leads to the formation of disfigured red blood cells (RBCs). The mutated hemoglobin triggers a series of reactions in which the structure of RBCs are deformed into a sickle cell shape that is characteristic of SCD.
With over 300,000 children born with SCD each year, it is one of the most common single-gene disorders in the world. Considering the large number of people affected by SCD, investigating effective treatment options has been a major priority of the scientific community for quite some time.
In a recent article published in the New England Journal of Medicine, results from a clinical trial investigating a new treatment option for SCD and beta thalassemia potentially indicate promise in identifying a solution for these diseases.
The basis of their clinical trial revolved around the different types of human hemoglobin: fetal and adult. The researchers found that patients with less severe SCD are adults who have high levels of fetal hemoglobin in their blood due to a mutation at a specific gene on chromosome 2 called BCI11A. Compared to normal adult hemoglobin, fetal hemoglobin has higher affinity for oxygen. This allows fetal hemoglobin to pick up more oxygen which helps compensate for the sickle RBCs that are unable to pick up oxygen effectively.
Sickle cell disease (SCD) is a common example of an illness resulting from a small mutation, specifically a point mutation, where a single base pair underwent deletion, incorrect insertion, or is changed altogether. When the gene where this mutation occurs codes for a subunit of hemoglobin, it leads to the formation of disfigured red blood cells (RBCs). The mutated hemoglobin triggers a series of reactions in which the structure of RBCs are deformed into a sickle cell shape that is characteristic of SCD.
With over 300,000 children born with SCD each year, it is one of the most common single-gene disorders in the world. Considering the large number of people affected by SCD, investigating effective treatment options has been a major priority of the scientific community for quite some time.
In a recent article published in the New England Journal of Medicine, results from a clinical trial investigating a new treatment option for SCD and beta thalassemia potentially indicate promise in identifying a solution for these diseases.
The basis of their clinical trial revolved around the different types of human hemoglobin: fetal and adult. The researchers found that patients with less severe SCD are adults who have high levels of fetal hemoglobin in their blood due to a mutation at a specific gene on chromosome 2 called BCI11A. Compared to normal adult hemoglobin, fetal hemoglobin has higher affinity for oxygen. This allows fetal hemoglobin to pick up more oxygen which helps compensate for the sickle RBCs that are unable to pick up oxygen effectively.
Image Source: qimono
Knowing this, the researchers used a gene editing tool called CRISPR to genetically change blood stem cells into cells that activate the production of fetal hemoglobin. In the clinical trial, the researchers added this altered blood stem cell infusion into a patient with SCD, which resulted in increased fetal hemoglobin levels and less severe SCD symptoms. A decrease in the symptoms also led to a reduced need for blood transfusions, a common treatment procedure for those with SCD.
Despite this clinical trial’s promising results, it is still important to note the limitations of the study. The extremely small sample size of a single patient at the time of the article’s publication means that it is too early to make any definitive conclusions on the usefulness of this method for the treatment of SCD. However, the researchers are continuing their research and since publication, the group has tested their method on three more SCD patients with similar success.
Another important limitation to this potential treatment method is that it involves the introduction of foreign elements into the body of patients. This led to side effects like pneumonia, abdominal pain, headaches, and acute respiratory distress syndrome. While these side effects are usually treatable, they further the discomfort experienced by the patients.
But overall, new treatment avenues are vitally important for the effective treatment of SCD and other diseases where a simple mutation results in significant damage inflicted throughout the body.
Despite this clinical trial’s promising results, it is still important to note the limitations of the study. The extremely small sample size of a single patient at the time of the article’s publication means that it is too early to make any definitive conclusions on the usefulness of this method for the treatment of SCD. However, the researchers are continuing their research and since publication, the group has tested their method on three more SCD patients with similar success.
Another important limitation to this potential treatment method is that it involves the introduction of foreign elements into the body of patients. This led to side effects like pneumonia, abdominal pain, headaches, and acute respiratory distress syndrome. While these side effects are usually treatable, they further the discomfort experienced by the patients.
But overall, new treatment avenues are vitally important for the effective treatment of SCD and other diseases where a simple mutation results in significant damage inflicted throughout the body.
Featured Image Source: mirerek8
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