Sickle Cell Anemia mutation
Sickle Cell Anemia mutation
What is sickle cell anemia?
Sickle Cell Anemia mutation is a disease that contains abnormal hemoglobin which means sickle hemoglobin. It affects red blood cells (RBC) as it causes the cells in a sickle shape. Sickle Cell Anemia, sometimes called Sickle Cell Disease, is an inherited disorder characterized by the abnormal production or secretion of the beta-carotene molecule, which is responsible for red blood cells’ ability to carry oxygen.
Sickle Cell Anemia- Symptoms
Symptoms vary, but most sufferers complain of fatigue, shortness of breath, and an inability to focus. Shortness of breath is often due to low platelet levels. Because the sickle cell anemia mutation depletes the body of hemoglobin, the oxygen needed to carry oxygen in and out of the cells is compromised. This allows oxygen to be carried only by blood cells and some white blood cells. This lack of oxygen can reduce the body’s immune system response and reduce the chances of illness.
Sickle cell anemia hemoglobin structure
Red blood cells are also called as erythrocytes that carry oxygen from lungs to rest of the body. Hemoglobin is the protein made by red blood cells. This pigment is red in colour that gives blood its red colour.
Hemoglobin carries oxygen from the lungs to rest of the tissues and returns carbon dioxide from the body tissues to the lungs again. Haemoglobin is a complex protein that circulates through the bloodstream carrying oxygen and nutrients to all tissues. A special type of hemoglobin, V-shaped or beta-shaped, is responsible for carrying oxygen to all body tissues and organs. In order to carry oxygen, the protein must be coated on the inside with iron.
Sickle cell anemia affects hemoglobin and thus do not deliver oxygen to the tissues efficiently. Sickled red blood cells have difficulty binding to oxygen. Sickle shape red blood cells block capillaries their sickle or collapsed shape is not efficient.
Sickle cell anemia mutation
Hb A/Hb A is the genotype of normal person. Hb A/Hb S is the genotype of mild sickle cell anemia. Hb S/Hb S is the genotype of person with sickle cell anemia.
Sickle cell anemia is caused by single nucleotide mutation in which thymine is in place of an adenine. SNP is called as single nucleotide polymorphism. Hemoglobin contains heme group, two alpha chains (chromosome 16, q arm) and two beta chains (chromosome 11, q arm). SNP for sickle cell anemia occurs on the 17th nucleotide of the beta chain. SNP codes for valine instead of glutamic acid.
Sickle cell anemia genetics
Sequence for Hb A is palindrome which is CCTGAGG. Sequence for Hb S is not a palindrome CCTGTGG. Hb A codes for glutamic Acid and HbS codes for valine. Mst II is the restriction enzyme which is used to detect Hb S. Mst II cuts at CCT(N)AGG–>A
where, N can be either be A or T that depends on the genotype.
Sickle cell anemia and malaria relationship
Plasmodium causes malaria and it spends most of its life cycle in red blood cells. But person with sickle cell anemia can either have mild or no malaria because plasmodium will not able to reproduce in sickle-shaped red blood cells.
Sickle cell less severe in people of Indian descent compared to those of African descent. The people of Indian descent contain 20- 30% fetal hemoglobin which resists sickling. This is because Fetal hemoglobin (HbF) change the phenotype of sickle cell anemia by inhibiting the deoxy sickle hemoglobin polymerization. Therefore, Fetal hemoglobin is not sickle shaped and able to transport oxygen efficiently.
Sickle cell anemia-Treatment
When it comes to sickle cell anemia, there are several ways to increase the chance of survival. Increased fluid intake can help to improve fluid retention and decrease the amount of hemoglobin breakdown. This allows to reduce the amount of red blood cells produced and improve child’s overall health. Increased fluid intake can also improve immune system response. Some physicians recommend that patients with sickle cell anemia take a daily supplement that contains vitamin K, folic acid, and niacin.