The most prevalent genetic disorder in the USA today is Sickle Cell Anemia (SCA) and affects the red blood cells, also known as erythrocytes or rbcs. Healthy rbcs are concave in the middle. This is because fetal cells lose their nuclei upon birth. This ennucleation causes the cell to sink in on itself. In SCA, the crescent-shaped erythrocytes are rapidly destroyed. This forces a rapid production of new ones. These cells are forced out before they are mature, causing them to retain their nuclei. Couples who believe they may carry the genes for the disease should consult a genetic counselor about sickle cell anemia prevention.
In order for someone to develop the disease, both parents must carry the recessive trait for a specific type of hemoglobin. This trait is called AS. In this case, there is one chance in four that their offspring will inherit the disease. There is also half a chance that they will carry the AS trait and one chance in four that they will neither carry the trait nor have the disease. If one parent has normal hemoglobin, Type AA, and the other has AS, there is half a chance that each child will have the trait but not the disease.
People who come from warm climates are more likely to be affected by SCA. It affects people of American African origin the most, with one in ten newborns carrying the AS trait and one in roughly 450 deliveries resulting in an infant with the disease. Hispanic newborns are half as likely to develop the trait and the disease. Other nationalities that are affected are people from Asiatic India, the Arab countries, Greece, Italy and Latin America.
The SCD gene is recessive. So why is it so prevalent? The reason for this is that people who carry the AS trait have an inherent protection from developing malaria. Notice that the nationalities that are affected by SCD are from countries that are situated in regions where malaria is a menace. Up until 2011, nobody knew why a heterozygous trait for one disease could protect people from another deadly condition.
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 signs and symptoms of SCA are the same as for any other form of hemoglobin deficiency. These are shortness of breath, dizziness, headaches, fatigue, coldness in the extremities, paler than normal skin and jaundice (evidenced by a yellow tinge in the whites of the eyes). SCA is also characterized by outbreaks of excruciating pain all over the body.
An SCA crisis occurs when the errant erythrocytes stick together and cut off blood flow, causing damage to major organs (lungs, liver and kidneys). This is also what causes the bouts of unbearable pain. A crisis may go on for hours and then resolve spontaneously or it may persist for days, up to a week or longer.
Currently in the United States, all newborn babies are routinely tested for the AS trait and for SCD. This paves the way for early treatment of the condition. So far, the only of preventing SCD is by having a frank discussion with a genetic counselor and making sometimes difficult decisions regarding family planning.
In order for someone to develop the disease, both parents must carry the recessive trait for a specific type of hemoglobin. This trait is called AS. In this case, there is one chance in four that their offspring will inherit the disease. There is also half a chance that they will carry the AS trait and one chance in four that they will neither carry the trait nor have the disease. If one parent has normal hemoglobin, Type AA, and the other has AS, there is half a chance that each child will have the trait but not the disease.
People who come from warm climates are more likely to be affected by SCA. It affects people of American African origin the most, with one in ten newborns carrying the AS trait and one in roughly 450 deliveries resulting in an infant with the disease. Hispanic newborns are half as likely to develop the trait and the disease. Other nationalities that are affected are people from Asiatic India, the Arab countries, Greece, Italy and Latin America.
The SCD gene is recessive. So why is it so prevalent? The reason for this is that people who carry the AS trait have an inherent protection from developing malaria. Notice that the nationalities that are affected by SCD are from countries that are situated in regions where malaria is a menace. Up until 2011, nobody knew why a heterozygous trait for one disease could protect people from another deadly condition.
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 signs and symptoms of SCA are the same as for any other form of hemoglobin deficiency. These are shortness of breath, dizziness, headaches, fatigue, coldness in the extremities, paler than normal skin and jaundice (evidenced by a yellow tinge in the whites of the eyes). SCA is also characterized by outbreaks of excruciating pain all over the body.
An SCA crisis occurs when the errant erythrocytes stick together and cut off blood flow, causing damage to major organs (lungs, liver and kidneys). This is also what causes the bouts of unbearable pain. A crisis may go on for hours and then resolve spontaneously or it may persist for days, up to a week or longer.
Currently in the United States, all newborn babies are routinely tested for the AS trait and for SCD. This paves the way for early treatment of the condition. So far, the only of preventing SCD is by having a frank discussion with a genetic counselor and making sometimes difficult decisions regarding family planning.
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