The most common genetic disease in the United States is an erythrocyte disorder known as Sickle Cell Disease (SCD). It is a form of anemia in which the red blood cells become bent like a scythe, instead of round and concave in the middle. This means they can become stuck in piles in the blood stream, where they cause problems. Because it is an inherited disorder, sickle cell anemia prevention should be discussed with a genetic counselor, who can outline the available options.
Both parents must carry the sickle cell trait for hemoglobin (Type AS) for the offspring to inherit the disease. If this is the case, there is a 25% chance that the child will have the disease, 50% chance that he or she will carry the trait and a 25% chance that they will have neither the trait nor the disease. If one parent has normal hemoglobin (Type AA) and the other has Type AS, there is a 50% chance that each child will carry the trait, but they will not get the disease.
While it is true that African Americans are more commonly affected by the disease than people of other nationalities, it does affect people of Latin American, Italian, Arabic, Greek and Asiatic Indian descent. In fact, people of Hispanic origin are half as likely to get SCD as someone of African American origin. Approximately 1 in 10 African American newborns have the trait and one in roughly 450 develop SCD.
We already know that the SA gene is recessive. If this is the case, why is it such a prevalent disease? The reason for this is that the AS trait confers greater survival with respect to malaria, a deadly condition caused by a parasite carried by mosquitoes and affecting half the world's population. Up until very recently, the reason for this was completely unknown.
A recent publication in the scientific journal, Cell, indicates that, finally, the molecular reasons for this are beginning to be unraveled. This is good news for most of the world, half of whom are affected by this deadly disease. It is not, sadly, much help for those affected by sickle cell.
A lot of the symptoms and signs of SCD are common to other forms of anemia. These include dizziness, headaches, extreme fatigue, shortness of breath, pale skin, jaundiced eyes and coldness in the extremities. The condition is also characterized by sudden episodes of debilitating pain throughout the entire body.
Episodes of severe pain are typical of a sickle cell crisis, in which the scythe-shaped erythrocytes stick together and restrict blood flow to the major organs (kidneys, liver, lungs) and to the musculoskeletal system. These episodes can last for a matter of ours or go on for a week or more.
All newborns in the United States are routinely tested for AS. This opens the door for early treatment of the disease. At the moment, the only way to prevent sickle cell disease is through genetic counseling and family planning. Research is ongoing to find ways of making it possible for individuals who have the disease to live comfortable and productive lives.
Both parents must carry the sickle cell trait for hemoglobin (Type AS) for the offspring to inherit the disease. If this is the case, there is a 25% chance that the child will have the disease, 50% chance that he or she will carry the trait and a 25% chance that they will have neither the trait nor the disease. If one parent has normal hemoglobin (Type AA) and the other has Type AS, there is a 50% chance that each child will carry the trait, but they will not get the disease.
While it is true that African Americans are more commonly affected by the disease than people of other nationalities, it does affect people of Latin American, Italian, Arabic, Greek and Asiatic Indian descent. In fact, people of Hispanic origin are half as likely to get SCD as someone of African American origin. Approximately 1 in 10 African American newborns have the trait and one in roughly 450 develop SCD.
We already know that the SA gene is recessive. If this is the case, why is it such a prevalent disease? The reason for this is that the AS trait confers greater survival with respect to malaria, a deadly condition caused by a parasite carried by mosquitoes and affecting half the world's population. Up until very recently, the reason for this was completely unknown.
A recent publication in the scientific journal, Cell, indicates that, finally, the molecular reasons for this are beginning to be unraveled. This is good news for most of the world, half of whom are affected by this deadly disease. It is not, sadly, much help for those affected by sickle cell.
A lot of the symptoms and signs of SCD are common to other forms of anemia. These include dizziness, headaches, extreme fatigue, shortness of breath, pale skin, jaundiced eyes and coldness in the extremities. The condition is also characterized by sudden episodes of debilitating pain throughout the entire body.
Episodes of severe pain are typical of a sickle cell crisis, in which the scythe-shaped erythrocytes stick together and restrict blood flow to the major organs (kidneys, liver, lungs) and to the musculoskeletal system. These episodes can last for a matter of ours or go on for a week or more.
All newborns in the United States are routinely tested for AS. This opens the door for early treatment of the disease. At the moment, the only way to prevent sickle cell disease is through genetic counseling and family planning. Research is ongoing to find ways of making it possible for individuals who have the disease to live comfortable and productive lives.
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