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Compound heterozygosity for two α‐globin gene defects, Hb taybe (α1; 38 or 39 minus thr) and a poly a mutation (α2; AATAA A → AATAA G ), results in a severe hemolytic anemia
Author(s) -
Pobedimskaya D. D.,
Molchanova T. P.,
Streichman S.,
Huisman T. H. J.
Publication year - 1994
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.2830470310
Subject(s) - gene , mutation , hemolytic anemia , genetics , globin , microbiology and biotechnology , biology , compound heterozygosity , chromosome , hemoglobinopathy , gene mutation , immunology
We have identified two α‐globin gene variations in an Arabian male with severe hemolytic disease through sequencing of amplified DNA of his α2‐ and α1‐globin genes. One of the abnormalities involves a CAC (ACC or CCA) deletion between codons 36 and 41 of the α1‐globin gene. This leads to the synthesis of an abnormal α chain with one instead of two threonine residues at positions 38–39 and to the formation of the unstable Hb Taybe. The second variation is a mutation located in the poly A site of the α2‐globin gene (AATAA A → AATAA G ) which is common among Arabian people. Family studies have shown that the two variations are located on opposite chromosomes. The hemolytic disease in this man, resembling Hb H disease, is likely the result of a severe downregulation of both α‐globin genes on the chromosome with the α2 poly A mutation, and the instability of the α‐Taybe chain being the product of an α 1‐globin gene; this leaves only one α2‐globin gene normally active. © 1994 Wiley‐Liss, Inc.