<prompt> Which among the following is not an autoimmune disease?Myasthenia gravisSystemic lupus erythematosusGraves diseaseSickle cell disease  <response>: Ans. d Sickle cell diseaseRef: Robbins pathology 9th ed. 211-15, 635 Sickle cell disease is a genetic condition which is characterized by mutation in beta globin chain of hemoglobin glutamic acid is replaced with valine in the 6th position of beta chain. Other given choices like SLE, Graves and MG are all autoimmune conditions. 