[Hemolytic anemia due to hemoglobin Evans in an Argentinean family].

Unstable hemoglobins are structural variants of the hemoglobin molecule, mostly originated by single amino-acid replacement in some globin chains. These changes affect molecule stability, leading to loss of solubility, precipitation, and cellular lysis. Patients carrying these unstable hemoglobins may present mild to severe chronic hemolytic anemia.

Hb S-San Martin: a new sickling hemoglobin with two amino acid substitutions [β6(A3)Glu→Val;β105(G7)Leu→Pro] in an Argentinean family.

A new sickling hemoglobin (Hb) detected in an Argentinean family from San Martín, Buenos Aires, Argentina, is hereby described. Two mutations were identified on the same β-globin gene resulting in a new variant named Hb San Martin. One mutation was found on exon 1, corresponding to Hb S [β6Glu→Val, GAG>GTG] and the second one on exon 3 at β105(G7)Leu→Pro, CTC>CCC.

[Severe hemolytic anemia due to hemoglobin Hammersmith].

Most of the hemoglobin variants are the result of single amino acid replacement in one of the globin chains. In many cases, these hemoglobinopathies are harmless, while in others they determine alterations in the physical and chemical properties, raising clinical manifestations of variable severity. In the unstable hemoglobinopathies, the changes reduce solubility, inducing the formation of precipitates of denaturated hemoglobin (Heinz bodies), which damage the membrane and finally destroy the red blood cells prematurely.

New evidence of red blood cell rheological disorders in beta-thalassaemia minor.

Haemorheological parameters, such as red blood cell deformability, membrane elastic modulus and membrane surface viscosity in twenty one thalassaemia heterozygous patients (14 beta0/beta and 7 beta+/beta) were compared with normal individuals (n = 15). Parameters were measured applying a laser diffractometric method (ektacytometry). Thalassaemia erythrocytes showed statistically significant lower deformability and higher elastic modulus.