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α‐thalassaemia masked by β gene defects and a new polyadenylation site mutation on the α2‐globin gene |
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| Authors: | Cornelis L. Harteveld Wytze P. Oosterhuis Christian H. H. Schoenmakers Hardjawardhama Ananta Snjezana Kos Margaretha Bakker Verweij Peter Van Delft Sandra G. J. Arkesteijn Marion Phylipsen Piero C. Giordano |
| Affiliation: | 1. The Reference Hemoglobinopathies Laboratory, Department of Human and Clinical Genetics (LDGA), Leiden University Medical Center, Leiden;2. Department of Clinical Chemistry, MCA City Hospital, Heerleen;3. Department of Clinical Chemistry, Elkerliek Hospital, Helmond;4. Department of Internal Medicine, ‘t Lange Land Hospital, Zoetermeer;5. Department of Clinical Chemistry, ‘t Lange Land Hospital, Zoetermeer, The Netherlands |
| Abstract: | We report three examples of chronic anaemia involving complex combinations of α‐ and β‐globin gene defects. The first case had a potential Hb H disease caused by the classic SEA/RW deletions masked by Hb E [β26(B8)Glu→Lys] in the homozygous state. The second had an unusual Hb H disease caused by compound heterozygosity for two different α2 polyadenylation site mutations masked by a β‐thalassaemia heterozygosity. The third had an intermediate α‐thalassaemia with considerable anaemia caused by an as yet unknown polyadenylation site (AATAAA>AATAAC) mutation in combination with a common RW deletion masked by a common Hb C [β6(A3)Glu→Lys] heterozygosity. Diagnostic methods, genotype/phenotype correlations and the chance of overlooking these combinations during risk assessment in a multiethnic society are discussed. |
| Keywords: | α ‐thalassaemia β ‐thalassaemia globin genes polyadenylation site mutation |