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Association of thalassaemia intermedia with a beta‐globin gene haplotype
Author(s) -
Thein S. L.,
Wainscoat J. S.,
Sampietro M.,
Old J. M.,
Cappellini D.,
Fiorelli G.,
Modell B.,
Weatherall D. J.
Publication year - 1987
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1987.tb06870.x
Subject(s) - haplotype , genetics , biology , hemoglobinopathy , beta (programming language) , restriction fragment length polymorphism , restriction enzyme , globin , gene , fetal hemoglobin , genotype , hemolytic anemia , immunology , fetus , pregnancy , programming language , computer science
Summary. We have identified 14 Asian patients with homozygous β° thalassaemia who had a mild clinical disorder related to an augmented production of haemoglobin F. None of their parents had an elevated level of Hb F. Restriction fragment length polymorphism analysis of the β‐globin cluster of these patients and a control group of Asian thalassaemia major patients showed that 6/14 of the thalassaemia intermedia patients were homozgyous for a particular 5′β‐globin haplotype (−+−++), in contrast to 1/42 of the thalassaemia major patients. Furthermore, the —+—++β haplotype is also associated with amelioration of disease severity in β thalassaemia in an Italian population. This β haplotype is linked to a DNA sequence variation 5′ (at position — 158) to the c γ globin gene which can be detected by the presence (+) of an Xmn I restriction enzyme site. The possible role of the Xmn I‐γ polymorphism in relation to this variant HPFH is discussed. We conclude that much of the observed clinical variability of β thalassaemia can now be explained by the inheritance of β thalassaemia chromosomes with different propensities for fetal haemoglobin production.