The shape of RBCs of sickle cell anaemia patients change to elongated sickle like structure. Give reason.

Explanation

In patients with sickle-cell anaemia substitution of glutamic acid by valine at the sixth position of the beta globin chain of the haemoglobin molecule. The substitution of amino acid in the globin protein is due to the single base substitution at the sixth codon of the beta globin gene from GAG to GUG. The mutant haemoglobin molecule undergoes polymerisation under low oxygen tension causing the change in the shape of RBC from biconcave disc to elongated sickle like structure.