Sickle Cell Anaemia

1. It is a hereditary blood disease found in Africa and America.

2. This disease is characterised by the presence of sickle shaped RBC under low oxygen pressure.

3. The sickle shape of RBC is due to the presence of a defective haemoglobin called haemoglobin S.

4. Sickle cell anaemia is a recessive character caused by the recessive genes Hb^s  Hb^s. The normal adult haemoglobin is produced by dominant genes Hb^A Hb^A.

5. The heterozygous (Hb^A Hb^S) persons are normal and they are said to have sickle cell trait. They are the carriers of sickle cell gene. They have only mild symptoms of sickle cell anaemia.



Sickle Cell Anaemia

7. Sickle cells have low oxygen carrying capacity.
8. The sickle cells have very short life span. They tend to clump together and are destroyed.
9. The defective cells rupture and block the blood flow to tissues.
10. This disease also causes pain, fever, swelling, jaundice and kidney infection.
11. The sickle cell anaemia kills the victims after the age of 20.
12. In malarial areas the heterozygous persons (sickle cell trait Hb^A Hb^s) are resistant to malaria.