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Technical Briefs |
-Thalassemia Mutations
Departments of
1
Pediatrics and
2 Obstetrics & Gynecology, National University of Singapore 119074, Singapore
3 The Childrens Medical Institute and Molecular Diagnosis Center, Department of Laboratory Medicine, National University Hospital, Singapore 119074, Singapore
4 Departments of Pediatrics and Gynecology & Obstetrics, The Johns Hopkins University School of Medicine, Baltimore, MD 21287
5 Department of Pathology, The University of Hong Kong and Queen Mary Hospital, Hong Kong, Peoples Republic of China
6 Departments of Medicine and Pathology, Boston University School of Medicine, Boston, MA 02118
aaddress correspondence to this author at: Department of Pediatrics, National University of Singapore, Level 4, National University Hospital, 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. |
-Thalassemia is the most common globin disorder in the world, and the severe forms are especially prevalent among Southeast Asians. It is a disorder of absent or reduced production of
-globin chains resulting from mutations in the
-globin gene cluster on chromosome 16p13.3. Most
-thalassemia mutations involve deletions of one (-
) or both (- -)
-globin genes, whereas point mutations within the
-globin genes (
T
or 
T) are much less frequent. Nonetheless, the number of point mutations that have been described has been steadily increasing, with >40 identified to date (1)(2).
The importance of nondeletional
-thalassemia mutations is underscored by the observation that patients with nondeletional hemoglobin (Hb) H disease (
T
/- -) are generally more severely affected and more likely to require transfusions compared with deletional Hb H disease patients (-
/- -) (3). There have also been a few reports of Hb H disease caused by homozygosity or compound heterozygosity of nondeletional mutations involving the
2-globin gene (
T
/
T
) (1)(3). Additionally, nondeletional Hb H disease involving the
2 codon 30 or codon 59 mutation can cause the fatal Hb H hydrops fetalis syndrome, especially if associated with large
-
-globin gene deletions (4). In certain regions of Southeast Asia, nondeletional Hb H disease can account for as many as 50% of all Hb H disease patients (3).
Several specific and reliable molecular tests have previously been developed to diagnose and screen the most common deletional (5)(6) and nondeletional (7)(8)
-thalassemia mutations. We now describe a multiplex minisequencing assay to detect seven Southeast Asian nondeletional mutations: Hb Constant Spring (
2 codon 142 TAA
CAA), Hb Paksé (
2 codon 142 TAA
TAT), Hb Quong
The following articles in journals at HighWire Press have cited this article:
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A. Y.-Y. Chan, H.-Y. Luo, W. Wang, D. H.K. Chui, E. S.-K. Ma, L.-C. Chan, and S. S. Chong Diagnostic Pitfall in PCR-Based {alpha}-Thalassemia Genotyping Resulting from a (G->C) Polymorphism at Nucleotide 71 3' to the {alpha}2-Globin Gene Termination Codon. Clin. Chem., March 1, 2006; 52(3): 536 - 537. [Full Text] [PDF] |
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