HBB and sickle cell disease: Only three genetic loci have been validated as strongly associated with higher HbF in sickle cell disease: the 5′ beta globin locus (HBB)[5], [6], [7], [8], [9], although not the sickle mutation; the BCL11A repressor of HbF [5], [6], [7], [8], [10], [11]; and the HS1L-MYB intergenic region [5], [6], [8], [12].