Sickle Cell Anaemia
Why in News?
On Monday, October 5, 2026, the Government of Odisha launched a landmark vaccination initiative at the District Headquarters Hospital in Angul, under the National Sickle Cell Anaemia Elimination Mission.
Genetic Cause and Inheritance
- Genetic Mutation: Sickle Cell Anaemia (SCA) is an autosomal recessive genetic disorder caused by a point mutation in the HBB gene on chromosome 11.
- Defective Haemoglobin: This mutation causes the body to produce abnormal haemoglobin known as Haemoglobin S (HbS) instead of normal Haemoglobin A (HbA).
- Disease vs. Trait:
- If a person inherits the mutated gene from both parents, they develop Sickle Cell Anaemia (SCA).
- If they inherit it from only one parent, they have the Sickle Cell Trait (SCT). They are healthy carriers who usually show no symptoms but can pass the gene to their children.
Symptoms and Physical Impact
- Sickle-Shaped Cells: Under low oxygen conditions, the red blood cells become rigid, sticky, and shaped like sickles or crescent moons, instead of being round and flexible.
- Vaso-occlusive Crises (Severe Pain): The rigid cells get stuck in tiny capillaries, blocking blood flow. This cuts off oxygen to tissues, causing sudden, excruciating pain attacks called "crises" in the bones, chest, and abdomen.
- Chronic Anaemia: Normal red blood cells live for 120 days. Sickle cells are fragile and break down (haemolyze) in just 10 to 20 days, leaving the patient chronically short of red blood cells, causing severe fatigue and pale skin.
- Dactylitis: Painful swelling of the hands and feet, which is often the earliest visible sign in infants.
- Organ Damage: Repeated blockages can cause silent strokes, acute chest syndrome, and permanent damage to vital organs like the liver, kidneys, and spleen.
Diagnosis
- Solubility Test: A quick, preliminary screening test to see if cells sickle under reduced oxygen.
- High-Performance Liquid Chromatography (HPLC): Used to isolate and accurately measure the exact percentages of normal and abnormal haemoglobin variants in the blood.
- Haemoglobin Electrophoresis: Another gold-standard laboratory technique used to confirm the presence of HbS.
Treatment and Management
- Pneumococcal Vaccines: As highlighted by the Odisha launch, keeping patients updated on pneumococcal and influenza vaccines is critical to preventing deadly secondary infections.
- Hydroxyurea: A foundational daily oral medication that prompts the body to produce Fetal Haemoglobin (HbF). HbF prevents cells from warping into the sickle shape, drastically reducing pain crises.
- Blood Transfusions: Used during emergencies (like a stroke or acute chest syndrome) to quickly increase the count of normal donor red blood cells.
- Curative Options: Bone Marrow (Stem Cell) Transplants and cutting-edge CRISPR-gene therapies can cure the disease, but they are incredibly expensive, require highly specific matching donors, and are currently inaccessible to the vast majority of rural patients.
Epidemiology and the Malaria Link
- High-Burden Communities: In India, the disease heavily impacts rural, marginalized, and tribal populations due to historical endogamy (marrying within the same community).
- The Malaria Connection: The genetic mutation originally persisted through evolution because individuals with the Sickle Cell Trait (carriers) possess a natural resistance to severe malaria. Consequently, the disease is heavily clustered in historically malaria-prone tropical regions across Africa, the Middle East, and India.
