Unstable alpha‐chain hemoglobin variants with factitious beta‐thalassemia biosynthetic ratio: Hb questembert (α131[H14] Ser→Pro) and Hb Caen (α132[H15] Val→Gly)
1993; Wiley; Volume: 42; Issue: 4 Linguagem: Inglês
10.1002/ajh.2830420407
ISSN1096-8652
AutoresHenri Wajcman, Corinne Vasseur, Y. Blouquit, J. Rosa, Dominique Labie, A Najman, O. Reman, M Leporrier, F. Galactéros,
Tópico(s)Hemoglobin structure and function
ResumoAbstract Hb Questembert [α131(H14) Ser→Pro] was found in several members of a French family suffering from congenital Heinz body anemia. The unstable hemoglobin was expressed in the peripheral red blood cells at a very low level. Globin biosynthetic studies revealed a high specific activity of the abnormal chain and an α‐/β‐labeling ratio similar to that of β‐thalassemia trait. Hb Caen [α132(H15) Val→Gly] is another unstable variant with the same globin biosynthesis abnormality. In both cases the structural modification is localized at the end of the H helix, a region encoded by the third exon. The mechanism for the unbalanced globin synthesis is not yet clear. It may be related 1) to a defect in chain assembly, 2) to an increased rate of degradation of the variant chain followed by the release of unlabeled β‐chains from the abnormal hemoglobin, thus leading to an apparent suppression of β‐chain synthesis, or 3) to a modified stability of the abnormal α‐globin mRNA. © 1993 Wiley‐Liss, Inc.
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