Hematies Hyperdenses et Sphérocytose

A 12-year old female, suffering from recurring episodes of icterus and abdominal pain, is hospitalized in emergency. She is not anemic but her hemogram reveals a high level of hyperdense red blood cells (32%; controls 0-2.5%) and an abnormal reticulocyte count (201 x 10(3)/microL; controls 29-84 x 10(3)/microL), indicating a 3.5 fold increase in RBC production. The same abnormalities are found in the patient's mother. The blood smear shows few spherocytes. RBC osmotic fragility is increased only after incubation. Hereditary spherocytosis is diagnosed following electrophoresis of membrane proteins which reveals a deficiency in band 3, a protein which links the lipid bilayer to the cytoskeleton. This case of hemolytic anemia-illustrates the physiopathologic and diagnostic significance of hyperdense RBC, which reflect the cell dehydration associated with the membrane disorder.