Question

Which of the following is true for sickle cell anaemia?

• A. Substitution of glutamic acid by valine at the sixth position of the beta globin chain
• B. Substitution of valine by glutamic acid at the sixth position of the beta globin chain
• C. Substitution of valine by glutamic acid at the fifth position of the beta globin chain
• D. Substitution of glutamic acid by valine at the fifth position of the beta globin chain

Answer 1

The correct option is A Substitution of glutamic acid by valine at the sixth position of the beta globin chain

Sickle cell anaemia is an example of point mutation in which thymine is replaced by adenine. Due to this replacement, glutamic acid is substituted by valine at the sixth position of the beta globin chain of the haemoglobin molecule. The mutant haemoglobin molecule undergoes polymerisation under low oxygen tension causing the change in the shape of the RBC from biconcave disc to elongated sickle like structure.