HBB actual mutation HBB "HBB — Hemoglobin, Beta" HBB HBB gene HBB gene gene hemoglobin – subunit beta (HBB) gene hemoglobin – subunit beta (HBB) gene HBB gene actual mutation HBB HBB HBB mutation hemoglobin – subunit beta (HBB) gene HBB HBB hemoglobin – subunit beta (HBB) gene HBB hemoglobin – subunit beta (HBB) gene HBB gene β-hemoglobin gene HBB caused by a single mutation HBB HBB HBB HBB gene gene HBB gene HBB HBB gene HBB HBB gene HBB gene, HBB HBB HBB HBB gene HBB gene, el gen HBB