Gene analysis of α-thalassemic abnormal hemoglobin, Hb Constant Spring, possessing a mutation at the terminal codon of α-globin gene *
The red cells isolated from 10 Thai subjects, who had been diagnosed as carriers of Hb Constant Spring with a mutation at the terminal codon of the α-globin gene, were used for analysis of the α-globin gene. Hb analysis was performed using the IEF and HPLC（BioAssist Q-HPLC and HLC-723G7）methods of the hemolysates prepared from the red cells. After extraction of DNA by a simple method using a kit, detection of the deletion type of α-thalassemia-2 or α-thalassemia-1 mutation was performed by the Gap-PCR method and that of the non-deletion type of α-thalassemia mutation was done by PCR-sequencing of the α-globin gene. Hb analysis revealed subjects with low or high abnormal Hb content close to Hb A2. These were deduced as Hb Constant Spring and Hb E. Additionally, a few subjects were with Hb H at the anodic site. The deletion type of two kinds of α-thalassemia-2 mutation, -α3.7 and -α4.2, was not present. That of the α-thalassemia-1 mutation was of only one type, --SEA. The non-deletion type α-thalassemia-like mutation possessing a mutation at terminal codon found in the subjects had not only the α-Constant Spring（αCS）gene but also the a-Pakse（αPakse）gene. Therefore, the genotypes of patients diagnosed as having Hb H disease in Thailand might be --SEA/αCSα or--SEA/αPakseα. Two subjects were carriers of Hb E, which is the most common hemoglobin variant in Thailand. This study may be useful for the analysis of hemoglobinopathies in the many people immigrating from Southeast Asian areas to Japan, especially Thailand, Vietnam, Cambodia, and the Philippines, since the αCS gene is the common α-thalassemia-like mutation causing Hb H disease in these areas. （Accepted on November ９，2004）
