Globin chain analysis: an important tool in phenotype study of hemoglobin disorders

Phenotype studies still occupy a key position in the diagnosis of hemoglobin (Hb) disorders. An additional dimension to the methods for diagnosis of Hb disorders which are mostly based on difference in charge of the Hb molecules may be brought by studying some properties of the globin chains. Among the methods proposed, reversed-phase liquid-chromatography (RP-LC) reveals differences in hydrophobicity allowing to discriminate between variants displaying identical charges. Thus, abnormal Hbs responsible for hematological disorders, such as chronic hemolytic anemia, erythrocytosis, or thalassemia like presentation, but with a charge similar to HbA or to that of a common variant may be revealed. Also RP-LC, which discriminates between the two types of gamma chains, may be of interest for diagnosis of hereditary persistence of fetal hemoglobin (HPFH) or for suggesting a haplotype in the case of sickle cell anemia.