HBD and sickle cell disease: In multiple papers by several labs studying CRISPR editing in sickle cell anemia, targeting the hemoglobin beta gene (HBB) with a CRISPR/Cas construct led, in a small number of cases, to a conversion of a segment of the HBB gene to that of hemoglobin delta (HBD), effectively creating a novel HBB/HBD chimeric gene [32,49,50].