The nondeletional types of hereditary persistence of fetal hemoglobin (ndHPFH) concern the continued synthesis of hemoglobin (Hb) F with either (G)γ or (A)γ chains in amounts varying from 5% to 30%. Several mutations have been identified in either the (A)γ or (G)γ promoter which are considered causative to the continued production of one of the two γ chains because the substitutions occur in sequence motifs essential for the expression characteristics of the γ-globin gene in the 3' position. We report the discovery of a T → C mutation at position -175 in the (A)γ promoter which was associated with a greatly increased level of Hb F (with mainly (A)γ) and a decreased level of Hb A in the one (Black) heterozygote who had a β(c) gene in trans. The same mutation has been observed in the (G)γ promoter of a Black heterozygote who had high levels of Hb F with (G)γ chains only. A detailed comparison between these two individuals indicated significant differences in the levels of Hb F and Hb A which may result from an additional mutation at position -158 in the (G)γ promoter.
|Original language||English (US)|
|Number of pages||5|
|State||Published - Jan 1 1989|
ASJC Scopus subject areas
- Cell Biology