<prompt> For the development of sickle cell disease, codon of aminoacid glutamate is replaced with codon of amino acid___ at the 6th position of beta globin gene -ValinePhenylalanineAspargineSerine  <response>: Ans. is a i.e., Valine Sickle cell disease is a common hereditary hemoglobinoopathy caused by a point mutation in b-globin that promotes the polymerization of deoxygenated hemoglobin, leading to red cell distortion, hemolytic anemia, micro- vascular obstruction, and ischemic tissue damage. Several hundred different hemoglobinopathies caused by mutations in globin genes are known, but only those associated with sickle cell disease are prevalent enough in the United States to merit discussion. Hemoglobin is a tetrameric protein composed of two pairs of globin chains, each with its own heme group. Normal adult red cells contain mainly HbA a2b2, along with small amounts of HbA2 a2d2 and fetal hemoglobin HbF; a2g2. Sickle cell disease is caused by a point mutation in the sixth codon of b-globin that leads to the replacement of a glutamate residue with a valine residue. The abnormal physiochemical properties of the resulting sickle hemoglobin HbS are responsible for the disease. 