Question

Find the difference among the people with genotype HbA HbA, HbA HbS and Hbs HbS, regarding sickle cell anaemia.

Answer 1

Sickle cell anaemia is an autosomal recessive disorder that is inherited from parents. It results in reduced oxygen carrying capacities of red blood cells.

Complete answer:
Sickle cell anaemia occurs because the shape of the red blood cells turns sickle-like in place of the normal round concave shape. This change in shape reduces the surface area as a result of which the oxygen carrying capacity also decreases. Most of the sickle cell anaemia cases has been reported in Africa.
Normal humans contain three different types of haemoglobin- haemoglobin A which contains two alpha and two beta chains, haemoglobin A2 which consists of two alpha and two delta chains and haemoglobin F that contains two alpha and two gamma chains.
Sickle cell anaemia occurs when haemoglobin S replaces both the beta globin chains of haemoglobin A now in the condition where HbA HbA is present both the parents have normal haemoglobin and thus the child also has normal haemoglobin.
In the second case HbA HbS one of the parents has normal haemoglobin whereas the other has sickle cell trait, in such a case the offspring has a fifty percent chance of having sickle cell disease. Whereas in the last case HbS HbS both the parents have sickle cell trait so there is a very high chance of the offspring to have sickle cell anaemia.
So in conclusion we can say people with HbA HbA do not develop sickle cell anaemia at all, people with HbA HbS themselves do not develop the disease but there is some chance of the offspring to develop the disease whereas people with HbS HbS themselves have sickle cell anaemia and chance of the offspring to have it is also higher.

Note: Sickle cell anaemia though classified as a disease is sometimes helpful for people living in malaria- stricken areas because the presence of this condition doesn’t allow the malarial parasite to cause disease.