Phenotypic expression of hemoglobins A2, E and F in various hemoglobin E related disorders

Routine screening for α-thalassaemia using an immunochromatographic strip assay for haemoglobin Bart's

“…b-thalassaemia heterozygosity is diagnosed in individuals with Hb A 2 A; Hb A 2 5 4.0%. 13,14 Polymerase chain reaction (PCR) and related methods are routinely utilized to identify b-thalassaemia mutations and six a-thalassaemia alleles common in Thailand (ie. a 0 -thalassaemia SEA & THAI deletions, a þ -thalassaemia 3.7 & 4.2 kb deletions, Hb Constant Spring and Hb Pakse´1 [5][6][7][8][9][10][11][12][13][14][15][16][17] ).…”

Measurement of HbA2by Capillary Electrophoresis for Diagnosing β-thalassemia/HbE Disease in Patients With Low HbF

“…This finding was consistent with a previous study that reported β-thalassemia/HbE or homozygous HbE patients who co-inherited the α-thalassemia-1 SEA type deletion had higher levels of HbA 2 than those who did not co-inherit the α-thalassemia-1 SEA type deletion. 19 These results imply that the reduced α-globin chains in β-thalassemia/ HbE or homozygous HbE patients who co-inherited the α-thalassemia-1 SEA type deletion preferentially bind to the d-globin chain.…”

Five Hemoglobin Variants in a Double Heterozygote for α- and β-Globin Chain Defects

“…It is also noteworthy that the identification of reduced Hb A 2 (α 2 δ 2 ) and the presence of the Hb QA 2 derivative (α QT 2 δ 2 ) in a patient with Hb Q-Thailand/Hb Tak double heterozygote or other similar Hb variants should have clinical implications. Recognition of this Hb A 2 variant is very important for the diagnosis and exclusion of β-thalassemia minor [16,17,18,19]. Since elevation of Hb A 2 is a characteristic of β-thalassemia carriers, the underestimated Hb A 2 could lead to a misdiagnosis of β-thalassemia heterozygote.…”