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Haemoglobin (Hb) G‐Philadelphia, Hb Stanleyville‐II, Hb G‐Norfolk, Hb Matsue‐Oki and Hb Mizushi can form a panel of α‐chain variants that overlap in their phenotype: the novel use of Sty I to screen for Hb G‐Philadelphia
Author(s) -
KHALIL M. S. M.,
TIMBS A.,
HENDERSON S.,
SCHUH A.,
HUSSEIN M. R. A.,
OLD J.
Publication year - 2011
Publication title -
international journal of laboratory hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.705
H-Index - 55
eISSN - 1751-553X
pISSN - 1751-5521
DOI - 10.1111/j.1751-553x.2010.01289.x
Subject(s) - restriction enzyme , microbiology and biotechnology , isoelectric focusing , phenotype , dna sequencing , hemoglobin variants , dna , restriction site , hemoglobin , genetics , biology , mutation , gene , enzyme , biochemistry
Summary Introduction: Haemoglobin (Hb) G‐Philadelphia mutation is a common alpha‐globin chain variant [α68(E17)Asn > Lys]. Combined high performance liquid chromatography (HPLC) and isoelectric focusing (IEF) can be used in a presumptive diagnosis of Hb G‐Philadelphia, but there are other α‐chain variants with a similar phenotype that cannot be excluded. Our aim was to develop a novel Sty I restriction enzyme assay to diagnose the common Hb G‐Philadelphia mutation and to identify any other variants with a similar phenotype by DNA sequencing. Methods: Thirty‐one cases given a presumptive diagnosis as Hb G‐Philadelphia by HPLC and IEF were subjected to DNA analysis by restriction enzyme digestion using Sty I. Negative cases were then subjected to DNA sequencing. Results: Twenty‐two cases (78.6%) of 28 cases amplified were tested positive for Hb G‐Philadelphia by Sty I restriction digestion. Sequencing of the six negative cases revealed two cases of Hb G‐Philadelphia with C→A mutation in codon 68 in α2 globin gene, plus one case each of Hb G‐Norfolk Hb Stanleyville‐II, Hb Matsue‐Oki and Hb Mizushi. Conclusion: A novel Sty I restriction enzyme can be used to confirm the commonest type of Hb G‐Philadelphia. DNA sequencing identified four other α‐chain variants with a similar HPLC and IEF phenotype.