A new hereditary persistence of fetal hemoglobin deletion has the
breakpoint within the 3' beta-globin gene enhancer
C Camaschella, A Serra, E Gottardi, A Alfarano, D Revello, U Mazza and G Saglio
Dipartimento di Scienze Biomediche e Oncologia Umana, Universita di Torino,
Italy.
A new deletion of the beta-globin gene cluster has been characterized in
two Italian brothers who are heterozygous carriers of a G gamma A gamma
hereditary persistence of fetal hemoglobin (HPFH). Restriction endonuclease
mapping and DNA sequencing of the region encompassing the breakpoint show
that the deletion starts 3.2 kilobases (kb) upstream from the delta gene
and ends within the enhancer region 3' to the beta- globin gene. Here the
deletion removes one of the four binding sites for an erythroid specific
transcriptional factor (NF-E1). The molecular comparison of the new
deletion with others of similar size and location but associated with a
delta beta-thalassemia phenotype suggests that the residual enhancer
element, relocated near gamma genes, may increase the fetal hemoglobin
(HbF) expression above the level observed in delta beta-thalassemia.
Volume 75,
Issue 4,
pp. 1000-1005,
02/15/1990
Copyright © 1990 by The American Society of Hematology
