Unstable hemoglobin Rush [beta 101(G3) Glu>Gln, HBB:c.304G>C] in a Brazilian family with moderate hemolytic anemia.

Hemoglobin Rush is an unstable variant generated by a mutation of the β-globin gene which causes amino acid replacement Glu>Gln in the central cavity of hemoglobin (G3). Many members of a Brazilian family of Italian descent have hemoglobin Rush. This is the second report in world literature. Clinical and laboratory features were retrieved and gene mutation was characterized. Hemoglobin electrophoresis, gene sequencing, and restriction fragment length polymorphism with Hpy188I were used to characterize it. In 13 affected members, hemoglobin ranged from 9.3 to 13.0 g/dL and reticulocyte count up to 12.8%. The intensity of hemolysis appeared to be linked to increased stress. The mutation was proved to be HBB:c.304G>C, beta 101(G3) Glu>Gln. Heterozygous hemoglobin Rush should be suspected when alkaline electrophoresis shows three bands, whereas isoelectric focusing and acid electrophoresis show only two. Adequate genetic counseling to avoid intermarriage should be provided because homozygous hemoglobin Rush is predicted to be clinically severe.