Medicine 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. 💡 Explanation The primary defect which leads to sickle cell anemia is ✓ Correct Answer: B. Replacement of glutamate by valine in B-chain of HbA