Comparison of the breakpoints of naturally occurring deletions associated with HBG upregulation. Naturally occurring deletions in both thalassemic and HPFH individuals with upregulated HbF levels are shown in relation to their location in the β-globin locus (numbers represent the human chromosome 11 coordinates from the hg38 genome assembly). The name and deletion type are indicated on the left, and the deletion associated with each condition is indicated by the blue bars. The percentage of HbF detected in patients with each condition who are heterozygous for the respective deletion is provided next to the condition name as well as the number of patients that this data were derived from. The core region has been indicated by a red bar with a dashed line indicating the corresponding region in all other deletions and the β-globin locus, which we have defined as the ∼1100 bp region between the 5′ end of the 1393 deletion and the 3′ end of the Croatian deletion (hg38 chromosome 11 coordinates 5 226 452 to 5 227 556). SEA, South East Asian.