short note on sickle cell anemia
Sickle cell anemia is a blood disorder that affects hemoglobin (pronounced: hee-muh-glow-bin), the protein found in red blood cells (RBCs) that helps carry oxygen throughout the body.
Sickle cell anemia occurs when a person inherits two abnormal genes (one from each parent) that cause their RBCs to change shape. Instead of being flexible and disc-shaped, these cells are more stiff and curved in the shape of the old farm tool known as a sickle — that's where the disease gets its name. The shape is similar to a crescent moon.
Red blood cells with normal hemoglobin (hemoglobin A, or HbA) move easily through the bloodstream, delivering oxygen to all of the cells of the body. Normal RBCs are shaped like discs or doughnuts with the centers partially "scooped out" and are soft and flexible. They can easily "squeeze" through even very small blood vessels.
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Sickle cell anemia (uh-NEE-me-uh) is the most common form of sickle cell disease (SCD). SCD is a serious disorder in which the body makes sickle-shaped red blood cells. “Sickle-shaped” means that the red blood cells are shaped like a crescent.
Normal red blood cells are disc-shaped and look like doughnuts without holes in the center. They move easily through your blood vessels. Red blood cells contain an iron-rich protein called hemoglobin (HEE-muh-glow-bin). This protein carries oxygen from the lungs to the rest of the body.
Sickle cells contain abnormal hemoglobin called sickle hemoglobin or
Sickle cells are stiff and sticky. They tend to block blood flow in the blood vessels of the limbs and organs. Blocked blood flow can cause pain, serious infections, and organ damage.
Normal Red Blood Cells and Sickle Cells
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. Figure B shows abnormal, sickled red blood cells blocking blood flow in a blood vessel. The inset image shows a cross-section of a sickle cell with abnormal (sickle) hemoglobin forming abnormal strands.
Sickle cell anemia is one type of anemia. Anemia is a condition in which your blood has a lower than normal number of red blood cells. This condition also can occur if your red blood cells don't contain enough hemoglobin.
Red blood cells are made in the spongy marrow inside the large bones of the body. Bone marrow is always making new red blood cells to replace old ones. Normal red blood cells live about 120 days in the bloodstream and then die. They carry oxygen and remove carbon dioxide (a waste product) from your body.
In sickle cell anemia, the number of red blood cells is low because sickle cells don't last very long. Sickle cells usually die after only about 10 to 20 days. The bone marrow can't make new red blood cells fast enough to replace the dying ones.
Sickle cell anemia is an inherited, lifelong disease. People who have the disease are born with it. They inherit two genes for sickle hemoglobin—one from each parent.
People who inherit a sickle hemoglobin gene from one parent and a normal gene from the other parent have a condition called sickle cell trait.
Sickle cell trait is different than sickle cell anemia. People who have sickle cell trait don't have the disease, but they have one of the genes that cause it. Like people who have sickle cell anemia, people who have sickle cell trait can pass the sickle hemoglobin gene on to their children.
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Sickle cell anemia is a disease which is caused by a mutation in which the amino acid at 6th position (glutamine) in the beta chain of hemoglobin is replaced by valine. The major characteristics of this disease are anemia (less functional RBCs) and a tendency of the red blood cells to change shape at low oxygen concentrations. The sickle cells are useless and have to be broken down. They tend to jam in capillaries and small blood vessels and prevent normal blood flow. A whole range of secondary symptoms is possible as a result. The kidneys and joints are particularly affected. The blocking of blood vessels causes pain in arms, legs, back and stomach which can be quite severe. Joints may become stiff and painful and hands and feet may swell....
Sickle-cell disease (SCD), or sickle-cell anaemia (or anemia, SCA) or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various complications. The sickling occurs because of a mutation in the hemoglobin gene. Life expectancy is shortened. In 1994, in the US, the average life expectancy of persons with this condition was estimated to be 42 years in males and 48 years in females. but today, thanks to better management of the disease, patients can live into their 50s or beyond.
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