<prompt> Which of the following is not seen on hemoglobin electrophoresis in sickle cell anemiaHbAHbA2HbFHbS  <response>: Ref Harrison 19 th ed pg 634 sickle cell syndromes are caused by a mutation in the b-globin gene that changes the sixth amino acid from glutamic acid to valine. HbS a2 b2 6 Glu-Val polymerizes reversibly when deoxygenated . No beta chains and therfther no HbA 