In order to provide a rapid method for identifying α-thalassemia 1 in a region with massive population and limited resources, we have tested a rapid screening strategy. Preliminary screening was done using a modified onetube osmotic fragility test (OF test) followed by RBC indices; Hb analysis and detection of α-thalassemia 1 with the Southeast Asian deletion (SEA type) were performed by PCR. One hundred and seventy-five adult Thai subjects were studied. Fifty-one of the 175 subjects (29.1%) were positive for a modified OF test. They all had significantly lower MCV and MCH but higher RDW-CV values as compared to the OF negative group. A successful identification of α-thalassemia 1 deletion using a direct PCR on cell lysates was demonstrated. Among the 51 OF-test-positive subjects, 7 were found to be α-thalassemia 1 carriers, 3 of whom were also carriers of Hb E. No α-thalassemia 1 was detected in the OF-test-negative group. A combination of a modified OF test and a direct PCR analysis on whole blood cell lysates would therefore provide an effective screening for α-thalassemia 1 in the regions where a program of prevention and control of the disease remains underserved.

The prevalence and molecular heterogeneities of the Hb variants found in this large cohort of the northern Thai people's should prove useful in developing a screening program, and for the performance of additional population genetics studies of hemoglobinopathy in the region.

Hb Constant Spring [Hb CS; α142, Term→Gln (TAA>CAA in α2)] is often missed by routine laboratory testing since its mRNA as well as gene product are unstable and presented at a low level in peripheral blood. This study aimed to analyze the efficacy of capillary electrophoresis (CE) and high performance liquid chromatography (HPLC) for detecting and quantifying Hb CS in 19 heterozygotes and 14 homozygotes with Hb CS as well as 10 Hb H-CS disease subjects who were detected by molecular analysis. In the CE electrophoregram, Hb CS was seen at zone 2 and was observed in all samples, while the chromatogram of Hb CS peaks was found in 26.32% heterozygotes, 42.86% homozygotes and 90% Hb H-CS disease subjects, respectively. In addition, the Hb CS levels in each group of subjects quantified by CE were significantly higher than those quantified by HPLC. Based on the CE method, the lowest Hb CS level was found in the heterozygotes, whereas the highest level was found in the Hb H-CS disease patients. Therefore, the CE method was superior to the HPLC method for detecting Hb CS. Furthermore, the level of Hb CS quantified by CE proved useful in screening heterozygotes and homozygotes with Hb CS as well as Hb H-CS disease.

Alpha (α) thalassemia (α-thal) is one of the most common inherited hemoglobin (Hb) disorders. This type of thalassemia is characterized by reduction or absence of the α-globin chain synthesis due to deletion or mutation of α-globin gene on chromosome 16 (16p13.3).More than 95% documented cases of α-thal report the deletion of one or both α-globin genes. 1 These gene deletions cause mild α + -thal and severe α 0 -thal. The most common mutations of α 0 -thal in the Thai population are the South-East Asian (--SEA ) and Thai (--Thai ) type deletions; the --SEA deletion is approximately 19.3 kb in length, covering both functional α-globin genes but leaving the ζ-globin gene intact, and the --Thai type deletion is approximately 34-38 kb in length, spanning over both α-globin genes as well as the ζ-globin gene. 2,3 -Thal --SEA -Thal --CR e120 |

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