Hemoglobinopathies are prevalent globally; diagnosis is complex in high genetic admixture populations like Brazil. We report, in two pediatric siblings, the first documented cases in Brazil of heterozygosity for hemoglobin (Hb) O-Arab with coinheritance of α-thalassemia (αα/-α4.2; -α3.7/-α4.2), resulting in microcytic and hypochromic anemia. Electrophoresis, high-performance liquid chromatography, HBB gene sequencing, and multiplex-polymerase chain reaction confirmed these complex genotypes. Although rare, Hb O-Arab significantly impacts clinical status, particularly in patients with coexisting hemoglobinopathies, such as α-thalassemia and Hb S, the latter resulting in a sickle cell disease form. This highlights the crucial role of molecular diagnostics, early screening, and genetic counseling in the accurate management and prevention of misdiagnosis in hemoglobinopathies.
Miranda et al. (Sun,) studied this question.