Cure of Sickle Cell Disease
(Published in the newspaper Amigoe on the 25th of February 2026)
In the previous article, treatment methods for sickle cell disease were discussed. However, these methods focus on combating the symptoms of sickle cell disease. These methods do not cure sickle cell disease. This article discusses two treatments that can cure sickle cell disease, namely bone marrow transplantation and gene therapy.
Bone marrow transplant
The only treatment that can cure sickle cell disease now is a stem cell or bone marrow transplant. In this process, the diseased bone marrow is replaced by healthy bone marrow from a suitable donor, allowing the body to make new, healthy red blood cells. However, this treatment is intensive and risky, and suitable donors, often a sibling with identical tissue typing, are scarce.
Gene therapy
The greatest hope for the future lies in gene therapy, a rapidly developing field of modern medicine. Recent techniques in the field of gene therapy are virus-based gene editing and the revolutionary CRISPR-Cas9 technology. These techniques focus on correcting the defective HBB gene. The HBB gene contains the blueprint for the β chain of hemoglobin in the red blood cells. This is the protein that binds and transports oxygen. The sickle cell mutation changes a single amino acid in this β chain, which in turn is the cause of sickle cell disease. Another possibility is to stimulate the body to produce more fetal hemoglobin.
The first patients to have undergone these treatments show spectacular improvements. The number of crises is less, the blood values are better, and in some cases, there is functional healing. Although these therapies are still expensive and complex for the time being, they are expected to play a major role in the definitive treatment of sickle cell disease in the coming years.
New method gene therapy using CRIPR-Cas9
An example of gene therapy using CRIPR-Cas9 is a promising new method developed by researchers from the Laat group, Erasmus MC and Sanquin. To understand this method, it is important to know that the unborn child does not have an HBB gene but another gene that has the same function. This is the HBG gene. However, in adults where the HBB gene has mutated, the HBG gene of the unborn child is still healthy.
This new technology therefore focuses on this still healthy fetal hemoglobin gene (HBG), which is normally only active before birth and is turned off after birth. This approach uses an innovative technique in which the still healthy fetal hemoglobin gene (HBG) is turned back on by bringing it closer to a genetic "switch" that can "turn on" the gene again. This is done with the help of CRISPR-Cas9, a kind of molecular scissors that can remove targeted pieces of DNA. By bringing the healthy fetal hemoglobin gene (HBG) closer to the genetic switch, it is turned back on. This allows the production of healthy hemoglobin to be restored.
This method was found to work in blood stem cells from both healthy donors and patients with sickle cell disease. Blood stem cells form the basis for the production of all blood cells in the body. The special thing about this strategy is that no external genes are added. This technique could also be used for other genetic disorders in which inactive genes play a role.
The attached picture shows schematically how the gene therapy takes place. The upper part of the picture shows the output situation. The (healthy) fetal hemoglobin gene (HBG) was turned off after birth and the (defective) adult hemoglobin gene (HBB) had taken over. After CRISPR-Cas9 technology has reduced the distance between the switch and the fetal hemoglobin gene, the (healthy) fetal gene (HBG) is turned on again.
This article is the last article in this series on sickle cell disease. We have seen that sickle cell disease is an inherited condition in which red blood cells take on an abnormal, sickle-shaped structure, resulting in painful attacks and organ damage. Treatment focuses mainly on preventing complaints, relieving pain and reducing complications, including with medication and supportive care.
For some patients, a bone marrow transplant offers a possible cure, as the faulty blood-forming system is replaced with healthy donor bone marrow. In addition, gene therapy is developing rapidly. This experimental approach seeks to correct the underlying genetic defect. Although still under research, these techniques offer hope for more sustainable solutions. With this we close the series, with attention to what is possible today, and what makes the future promising.
Next series
The next series is about shade trees on Curaçao. The earth is warming. Temperatures are rising. The number of hot days is also increasing. It will also be warmer during the night. We feel this especially where a lot has been built. Concrete and asphalt retain the heat accumulated during the day for a long time and release the heat again at night. In general, the increasing heat makes it increasingly unpleasant to be outside on hot days. This is especially the case in the urban environment.
Planting trees for shade contributes to a solution to this problem. Shade trees prevent the skin from being exposed to direct radiation from the sun. Shade trees also lower the air temperature. The upcoming series will discuss the temperature rise because of climate change, the importance of shade trees and how to plant them. Also, some examples of shade trees that are suitable to be planted in the city are discussed in depth.