Loss of three genes results in Hb H (4[beta] chains) disease, a moderate hemolytic anemia, while loss of all four genes is incompatible with independent life.
IEF provides excellent separation of many hemoglobin variants and detects fast-migrating or low concentration hemoglobin variants such as Hb H, Hb Bart's, and delta chain variants.
* Hb H and Hb Bart's are more readily detected and measured by CE than by the HPLC method (4)
The tetramers Hb Barts ([gamma]4) and Hb H ([beta]4), and Hb [F.sub.1], the acetylated form of Hb F, all elute before chromatogram integration; they therefore are not indicated on the chromatogram report.
Visual examination of the elution pattern for each specimen is required and is particularly important for laboratories with a patient population at high risk for [alpha]-thalassemia, Hb H disease, and Hb Barts hydrops fetalis.
If there is a co-inheritance of Hb H and Hb New York, preferential synthesis of the unstable Hb New York, the small number of a chains available to synthesize Hb A, and the high excess of [[beta].sup.A]- and [[beta].sup.NY]-chains, which precipitate in the erythrocyte precursors and cause ineffective erythropoiesis, lead to aggravation of the anemia.
The elements of one approach include a CBC, Hb H test, ferritin, HPLC for Hb [A.sub.2] and F quantification, and detection of any Hb variants followed by electrophoresis at both alkaline and acid pH.
This observation is variable among the thalassemia syndromes, however, with notable increases in RDW in the setting of Hb H disease and [delta] [beta]-thalassemia minor (1).
Conventional methods, including erythrocyte indices and morphology, Hb electrophoresis, quantitation of Hb [A.sub.2], Hb E, and Hb F, and detection of erythrocytes containing Hb H inclusion bodies, provide an accurate diagnosis (1-4).
In Hb H disease, there were one or two abnormal peaks present at the retention time of 1 min, before the Hb F peak.
Although these data support the mechanism we propose, they do not address the potential impact of the ability of Hb H (a tetramer of Hb [beta]-chains present in [alpha]-thalassemias) to trap NO.
Hb H was prepared by separating the [alpha]- and [beta]-chains of Hb A and allowing the isolated [beta]-chains to spontaneously form tetrameric Hb H .