Different haplotypes might be associated with different clinical phenotypes or disease severity.41 Using Ensembl and HaploReg version 4.1,42 we annotated each of the 27 markers in linkage disequilibrium at r2≥0.2 with rs334 (Table S1). Nine sites were marked on histones as promoters or enhancers, possibly implicating differential expression of HBB, HBD (MIM: 142000), HBE1 (MIM: 142100), or HBG2 (MIM: 142250). Three of these nine sites, rs334, rs73402608, and rs112336602, were also annotated as bound by proteins, possibly implicating the same four genes. In addition, rs1039215 is correlated with gene expression, most strongly with HBG2 (Table S2).