Non-thalassemic phenotype associated with the -83 (G > A) mutation of the ß-globin gene promoter (HBB: c.-133G > A).

ABSTRACT

The -83 (G > A) mutation of the ß-globin gene promoter (HBB c.-133G > A) was first reported in an adult male patient with mild thalassemic indices, suggesting that this may be a mild ß(+)-thalassemia (ß(+)-thal) allele. In this report, we present data from several patients who are simple heterozygotes for the -83 mutation, or compound heterozygotes for -83 and Hb S (HBB c.20A > T) or ß-thal. These cases illustrate that the -83 sequence variant is not associated with a thalassemic phenotype. This has important implications for carrier screening and genetic counseling, particularly since the -83 mutation is relatively common in African and Hispanic populations.