Hemoglobin subunit beta gene (HBB) sickle mutation site (HBB)

The HBB gene DNA at the sickle mutation codon refers to the specific genomic sequence within the Hemoglobin Subunit Beta gene where a single nucleotide polymorphism (rs334) occurs. This mutation involves an adenine to thymine (A to T) substitution at the sixth codon (GAG to GTG), which replaces a glutamic acid residue with valine in the beta-globin protein (UniProt P68871). This molecular change causes hemoglobin S (HbS) to polymerize under deoxygenated conditions, leading to the characteristic sickling of red blood cells and subsequent vaso-occlusive crises (NIH, 2023). As a therapeutic target, this DNA sequence is the focus of precision genome editing technologies, such as CRISPR/Cas9 and base editors, which aim to directly revert the mutation to the wild-type sequence (DeWitt et al., 2016). Unlike traditional gene therapies that add a functional gene or induce fetal hemoglobin, targeting this specific codon provides a path to permanent genetic correction of the endogenous locus. Successful modification of this target in hematopoietic stem cells can restore the production of functional adult hemoglobin (HbA) and potentially cure sickle cell disease (Newby et al., 2021). However, therapeutic application requires high precision to avoid off-target effects and ensure long-term safety in the bone marrow environment (Kanter et al., 2022).

Other names

HBB codon 6rs334Sickle cell mutation siteHBB:c.20A>TBeta-globin gene sickle mutationHBB Glu6Val mutation site

Direct genomic correction of the A to T point mutation at codon 6 of the HBB gene using site-specific nucleases or base editing to restore the wild-type GAG sequence and normal beta-globin production (DeWitt et al., 2016; Newby et al., 2021).