Genome-wide association studies have revealed 3 loci consistently associated with HbF level and β-globin disorder severity, across various ethnic backgrounds. These include the β-globin cluster itself on chromosome 11, the HBS1L-MYB intergenic interval on chromosome 6, and BCL11A on chromosome 2. A representative Manhattan plot is shown from the CSSCD cohort. Figure courtesy of Guillaume Lettre (Montreal Heart Institute).