A 4-Year-Old Patient Is Presented in the Pediatric Clinic with Microcytic

A 4-year-old patient is presented in the pediatric clinic with microcytic anemia. An analysis of his blood by
Non-denaturing electrophoresis reveals the following composition of hemoglobin isoforms: HbF = 75%, HbA
1 = 23%, HbA2 = 2%, and HbS = 0%. Using these data, it is possible to determine that the infant is most likely homozygous for which of the following?

A) complete deletion of the a-globin locus
B) complete deletion of the b-globin locus
C) mutation in the promoter of the b-globin genes
D) nonsense mutation in the a-globin genes
E) nonsense mutation in the b-globin genes