Which of the following abnormal hemoglobins, found frequently in individuals from Southeast Asia, migrates with hemoglobin A2 on cellulose acetate electrophoresis?

Which of the following abnormal hemoglobins, found frequently in individuals from Southeast Asia, migrates with hemoglobin A2 on cellulose acetate electrophoresis?

• A. Hemoglobin E
• B. Hemoglobin D
• C. Hemoglobin C
• D. Hemoglobin Lepore

Answer: (A)

On alkaline cellulose acetate electrophoresis, hemoglobins separate by net charge. Hemoglobin E, common in Southeast Asia, has a beta-globin mutation that changes its charge enough to migrate in the same region as HbA2. The Glu to Lys substitution at the beta-globin gene alters the molecule’s electrophoretic mobility, so HbE runs with HbA2 under these conditions. This geographic association plus the characteristic co-migration with HbA2 makes it the best match for the described scenario. The other listed variants have different migratory patterns or are more typical of other populations, so they wouldn’t be expected to co-migrate with HbA2.

On alkaline cellulose acetate electrophoresis, hemoglobins separate by net charge. Hemoglobin E, common in Southeast Asia, has a beta-globin mutation that changes its charge enough to migrate in the same region as HbA2. The Glu to Lys substitution at the beta-globin gene alters the molecule’s electrophoretic mobility, so HbE runs with HbA2 under these conditions. This geographic association plus the characteristic co-migration with HbA2 makes it the best match for the described scenario. The other listed variants have different migratory patterns or are more typical of other populations, so they wouldn’t be expected to co-migrate with HbA2.