The primary defect which leads to sickle cell anemia is: (A) An abnormality in porphyrin part of hemoglobin, (B) Replacement of glutamate by valine in B-chain of HbA, (C) A nonsence mutation in the B-chain of HbA, (D) Substitution of valine by glutamate in the A-chain of HbA.
Answer is B. None