FETAL HEMOGLOBIN EXPRESSION IN COMPOUND HETEROZYGOTES FOR -117(G-]A) (A)GAMMA HPFH AND BETA(O)39 NONSENSE THALASSEMIA

The -117(G-->A) (A) gamma hereditary persistence of fetal hemoglobin (Greek HPFH) and beta(o)39-thal mutations are rather frequent in Sardinia so that their interaction is to be expected, Characterization of eight compound heterozygotes for these defects indicated that HPFH was linked to haplotype VII and beta(o)39-thal to haplotype II, Haplotype II beta(o)39-thal chromosome carries the (A) gamma(T) gene which is a useful marker of gamma-gene expression, Since the Hb F level in these compound heterozygotes was significantly higher than in 46 - 117 HPFH carriers, the (A) gamma(I), (A) gamma(T), and (G) gamma globin level was determined, (A) gamma(T) was underexpressed while (G) gamma was significantly increased, which suggests that in -117 (A) gamma HPFH/beta(o)39-thal healthy subjects the increase in Hb F production is determined only by the -117 mutated (A) gamma gene and the adjacent (G) gamma gene, (C) 1995 Wiley-Liss, Inc.