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.
In order for a child to develop SCA, both parents must carry the trait for sickle cell hemoglobin (Type AS). If so, there is a 50% chance that the offspring will carry the trait and a 25% chance that it will either carry the trait or not. On the other hand, if one parent has the AS trait and the other has normal hemoglobin (Type AA), then there is a 50% chance that their children will carry the trait but they will not inherit 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.
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.
Today, all neonates in the USA are tested for AS at birth. This allows early access to treatment. For now, the only way to prevent SCA is for prospective parents to be tested for the trait and discuss the results with a genetic counselor. A genetic counselor is trained to discuss the options the would-be parents have, given the results of the blood tests.
In order for a child to develop SCA, both parents must carry the trait for sickle cell hemoglobin (Type AS). If so, there is a 50% chance that the offspring will carry the trait and a 25% chance that it will either carry the trait or not. On the other hand, if one parent has the AS trait and the other has normal hemoglobin (Type AA), then there is a 50% chance that their children will carry the trait but they will not inherit 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.
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.
Today, all neonates in the USA are tested for AS at birth. This allows early access to treatment. For now, the only way to prevent SCA is for prospective parents to be tested for the trait and discuss the results with a genetic counselor. A genetic counselor is trained to discuss the options the would-be parents have, given the results of the blood tests.