HBB loss of heterozygosity in the hemopoietic lineage gives rise to an unusual sickle-cell trait phenotype

We report, in a constitutionally heterozygous carrier of the sickle-cell trait, an abnormally low HbS level (12%) caused by a somatic deletion of the HBB gene (βS allele) that occurred presumably in an early precursor of the hematopoietic lineage.