Differential Diagnosis

• Single most likely diagnosis:
  • Hb E disease: The presence of 80.5% Hb E in the hemoglobin electrophoresis results strongly suggests this diagnosis. Hb E is a variant of hemoglobin caused by a point mutation in the beta-globin gene, leading to the substitution of glutamic acid for lysine at position 26. This mutation is the same as that found in Hb C (glutamic acid to lysine substitution, but at a different location in the beta gene). Hb E disease is characterized by a mild microcytic anemia, which is consistent with the patient's low MCV (51.7 fL) and mild anemia (HGB 10.6 g/dL). The low MCV is due to the reduced ability of Hb E to carry oxygen, leading to a compensatory increase in red blood cell production and, consequently, smaller red blood cells.
• Other Likely diagnoses:
  • Hb E trait: This is a less severe form of Hb E disease, often asymptomatic or with mild anemia. However, given the patient's age and the degree of anemia, Hb E disease is more likely.
  • Alpha-thalassemia: This could also present with microcytic anemia, but the hemoglobin electrophoresis results do not support this diagnosis as the primary issue.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Beta-thalassemia major: Although less likely given the specific hemoglobin electrophoresis results, beta-thalassemia major can present with severe anemia and would require immediate intervention. The presence of 13.8% Hb F (fetal hemoglobin) could be seen in beta-thalassemia, but the high percentage of Hb E points more towards Hb E disease.
• Rare diagnoses:
  • Other hemoglobinopathies: There are many other types of hemoglobinopathies that could present with abnormal hemoglobin electrophoresis results. However, the specific pattern seen here (high Hb E, presence of Hb F and Hb A2) is most consistent with Hb E disease.
  • Sickle cell disease: This would typically present with a different hemoglobin electrophoresis pattern (primarily Hb S) and is less likely given the results provided.

Geographical Location and Population Most Affected

Hb E disease is most commonly found in Southeast Asia, particularly in Thailand, Cambodia, and parts of India. It is also found in populations that have migrated from these areas. The high prevalence in these regions is due to the historical selection pressure from malaria, as carriers of the Hb E trait may have a survival advantage against malaria.

Final Diagnosis/Interpretation

The final diagnosis is Hb E disease. This diagnosis is based on the high percentage of Hb E on hemoglobin electrophoresis, the presence of microcytic anemia (low MCV), and the typical age and geographical distribution of the disease. The mutation leading to Hb E disease (same amino acid substitution as in Hb C but at a different location in the beta gene) affects the red blood cells by reducing their ability to carry oxygen efficiently, leading to a compensatory increase in red blood cell production and smaller cell size.