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This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: clinchem.2004.044396v1 51/3/641    most recent Submit an electronic Letter to the Editor about this paper Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Sutcharitchan, P. Articles by Chong–, S. S. Search for Related Content PubMed PubMed Citation Articles by Sutcharitchan, P. Articles by Chong–, S. S. Related Collections Molecular Diagnostics and Genetics Hematology Automation and Analytical Techniques

Hemoglobin H Disease Classification by Isoelectric Focusing: Molecular Verification of 110 Cases from Thailand

¹ Division of Hematology, Department of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Departments of² Pediatrics, ³ Obstetrics/Gynecology, and⁴ Laboratory Medicine, National University of Singapore and Hospital, Singapore, Singapore;⁵ Departments of Pediatrics and Gynecology/Obstetrics, and McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD

^aaddress correspondence to this author at: Department of Pediatrics, National University of Singapore, Level 4 NUH, 5 Lower Kent Ridge Road, Singapore 119074, Singapore; fax 65-6779-7486, e-mail paecs@nus.edu.sg

The first 300 words of the full text of this article appear below.

Hemoglobin (Hb) H disease is a mild to severe form of -thalassemia caused by the absence/inactivation of three of four -globin genes. As a result, there are insufficient -globin chains to form HbA (₂ß₂), the excess ß-globin chains forming unstable HbH (ß₄) (1), which precipitates and attaches to the erythrocyte membrane to cause membrane dysfunction and hemolysis (2). Genetically, there are two types of HbH disease, deletional HbH disease caused by compound heterozygosity for a double -globin gene deletion on one chromosome and a single -globin gene on the other (–/– –), and nondeletional HbH disease caused by compound heterozygosity for a double -globin gene deletion and a point mutation or small deletion/insertion on a third -globin gene (^T/– – or ^T/– –) (2). Generally, patients with nondeletional HbH disease present with a more severe phenotype than those with deletional HbH disease (1)(2).

HbH disease is particularly prevalent in Southeast Asia because of the high frequency of -thalassemia carriers in these areas (1)(2). In northern Thailand, 1.5% (1 in 65) of babies are expected to be born with HbH disease (3). In addition, nondeletional HbH disease with ^{Constant Spring} (HbHCS) is very common in Thailand, where 40–50% of patients with HbH disease have nondeletional HbH with ^{Constant Spring} (4).

Since the 1980s, isoelectric focusing (IEF) has been widely used in the identification of hemoglobin variants and in the diagnosis of HbH disease and HbBarts hydrops fetalis because of the good separation of HbBarts, HbH, and HbCS tetramers in IEF gels. The accuracy of IEF in HbH disease classification, however, is unknown. To evaluate the accuracy of IEF in predicting -globin genotype, we analyzed the genotypes of 110 Thai patients identified as . . . [Full Text of this Article]