About Sickle-Cell Disease
- The Red Blood Cells in the blood contains a protein called hemoglobin, which carries oxygen throughout the body.
- Normally, hemoglobin is smooth, round, disk-shaped and flexible, allowing the RBCs to flow smoothly through our bloodstreams.
- In case of patients with sickle-cell disease, the gene that codes for hemoglobin is genetically mutated making the hemoglobin sickle shaped.
- The abnormal hemoglobin forms rods that clump together distorting the shape of the RBCs.
- The distorted RBCs become curved and rigid taking the shape of a C-shaped sickle and hence the name.
- This results in deformation and break down of red blood cells in the blood.
- Sickle cell disease is an inherited blood disorder that can be acquired from either or both the parents who carry the defective gene.
- Those with the sickle-cell trait have one normal HbA allele and one abnormal HbS allele, whereas affected individuals have both abnormal HbS alleles. If both the parents are the carriers, then there is a 25% chance of producing an affected offspring.
- The sickle-shape and rigidity of the RBCs make it difficult to travel through the blood streams and hence the oxygen-carrying capacity of the blood. This oxygen deprivation to tissues and organs can lead to:
- Severe pain called ‘crises’
- Damage to organs
- Repeated pneumonia
- Swelling of hands and feet
- Enlargement of the spleen
- If the RBCs are severely distorted and become rigid, it can lead to a low-blood condition called anemia, as the distorted RBCs survive only for 10-20 days compared to 120 days in normal condition.
- Currently there is no cure to sickle-cell disease.
- Low-hemoglobin conditions are usually treated with blood-transfusions.
- The other remedy is bone marrow transplant but they carry the risk of rejection as the stem cells are taken from different individual.
Genetic Cure to SCD
- The researchers are working on a genetic engineering solution to treat SCD.
- The treatment involves removal of stem cells from the patient’s bone marrow.
- The stem cells so removed are genetically modified.
- The genetically modified cells are infused back in the bone marrow and helps form healthy RBCs.
Incidence of SCD
- The disease is most common in sub-Saharan Africa.
- Other regions known for the incidence of SCD are Southern Europe, Middle East and Asia including India.
- In India, prevalence of sickle cell trait is high in central India especially Maharashtra, Chhattisgarh and Odisha.
Global Initiatives to fight SCD
- In 2008, the UN General Assembly, recognizing sickle cell disease as a public health concern, established June 19 as World Sickle Cell Day.
- The Global Sickle Cell Disease Network is periodically conducting the Global Congress on Sickle Cell Disease staring from 2012.
- The 3rd and the latest Global Congress on Sickle Cell Disease and Bone Marrow Transplantation was held in Bhubaneswar in 2017.