SICKLE CELL ANEMIA M.Murat Güçlü 224 EFE DEMİR – B

What is Sickle Cell Anemia (SCA)? First described in Chicago in 1910 by James Herrick as an inherited condition that results in a decrease in the ability of red blood cells to carry oxygen throughout the body Sickle red blood cells become hard and irregularly shaped (resembling a sickle) Become clogged in the small blood vessels and therefore do not deliver oxygen to the tissues. Lack of tissue oxygenation can cause excruciating pain, damage to body organs and even death.

Mechanism  Red blood cells (RBC)  Contain a special protein called haemoglobin (Hb)  Hb is the component that carries oxygen from the lungs to all parts of the body  Most people have only hemoglobin type – Hb A within RBC (normal genotype: Hb AA)  Sickle Cell: HbS  S similar to A, but one structural change  Other types: HbC, HbD, and HbE

Mechanism -HbS  When sickle haemoglobin (HbS) gives up its oxygen to the tissues, HbS sticks together › Forms long rods form inside RBC › RBC become rigid, inflexible, and sickle-shaped › Unable to squeeze through small blood vessels, instead blocks small blood vessels › Less oxygen to tissues of body  RBCs containing HbS have a shorter lifespan › Normally 120 days › Chronic state of anaemia

Normal and Sickled Red Blood Cells in Blood Vessels Figure B shows abnormal, sickled red blood cells clumping and blocking the blood flow in a blood vessel. The inset image shows a cross-section of a sickled red blood cell with abnormal strands of hemoglobin Figure A shows normal red blood cells flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.

TRAIT  Sickle haemoglobin (S) + Normal haemoglobin (A) in RBC  Adequate amount of normal Hb (A) in red blood cells  RBC remain flexible  Carrier  Do Not have the symptoms of the sickle cell disorders, with 2 exceptions 1.Pain when Less Oxygen than usual (scuba diving, activities at high altitude (12,000ft), under general anaesthesia) 2.Minute kidney problems

Three common types of Sickle Cell Disorders 1.) Sickle Cell Anemia  Sickle haemoglobin (HbS) + Sickle haemoglobin (HbS)  Most Severe – No HbA

2.Hemoglobin S-C disease Sickle haemoglobin (HbS) + (HbC) 3.Hemoglobin S-Beta thalassemia Beta thalassaemia gene reduces the amount of HbA that can be made Sickle haemoglobin (HbS) + reduced HbA Milder form of Sickle Cell Disorder than sickle cell anemia

Medical Complications 1. pain episodes 2. strokes 3. increased infections 4. leg ulcers 5. bone damage 6. yellow eyes or jaundice 7. early gallstones 8. lung blockage 9. kidney damage and loss of body water in urine 10. painful erections in men (priapism) 11. blood blockage in the spleen or liver (sequestration) 12. eye damage 13. low red blood cell counts (anemia) 14. delayed growth

REFERENCES : Another Great Site information, Counselling and Caring for those with Sickle Cell Disorders and their families: UK based Sickle Cell Disease Association of America The Human Genome Project Sickle Cell Education Site at American Sickle Cell Anemia Association ASCAA was founded in 1971 and is the oldest sickle cell research, education, and social services organization in the United States.