SICKLE CELL DISEASE PREVENTION WITH PGD

Sickle cell anemia, or sometimes referred to as "Sickle cell disease" is an inherited type of anemia where red blood cells (which are responsible for carrying oxygen from the lungs to the rest of the body) are sickle shaped. Sickle cells contain abnormal hemoglobin called sickle hemoglobin or hemoglobin S. Sickle hemoglobin causes the cells to develop a sickle shape. These sickle shaped red blood cells can possibly clog sections of blood vessels which means oxygen cannot be carried properly to the rest of the organs, thus, causing episodes of severe pain.  

Abnormal sickle-shaped red blood cells have a shorter life-span compared to regular round shaped red blood cells and they usually die in about 10-20 days, and unfortunately they cannot be quickly replaced with new ones. This causes a shortage of red blood cells until the new ones are produced, causing anemia. The symptoms of the disease usually begin in early childhood and symptoms of sickle cell anemia are, low count of red blood cells, shortness of breath, developmental growth and delay in children and high blood pressure. Treatment of sickle cell anemia involves measures to reduce the severity and frequency of episodes of sickle cell crises.

Sickle cell disorder is caused by the HBB gene mutation. Sickle-cell anemia is caused by a mutation in the ß-globin chain of hemoglobin, caused by an amino acid substitution of Glu to Val at the sixth amino acid position in the beta-chain hemoglobin protein. The substitution causes a mutation (abnormality) which causes the hemoglobin to distort the red blood cells into a sickle shape.

Pattern of inheritance is autosomal recessive, which means, in order to have sickle cell anemia, the patient will need to acquire the mutation carrying gene allele from both parents. If both male and female patients have the sickle cell carrying gene allele, then there is a very high risk of exposing their offspring to this disease. 

If a person only acquires one allele from a single parent (whereas the other parent is not a carrier and is free of sickle cell disease), the person remains a carrier of the disease. A carrier is not at any risk. However, if both parents are carriers of the sickle cell mutant gene, then there is a 25% chance of passing it down to the offspring. In other words, having the sickle cell trait itself is not likely to cause a person to develop sickle cell disease. But if two people with the trait are going to conceive a child then there is a one in four chance that child will be born with sickle cell anemia.

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Author: lowcostivf.net