An erythroid-specific enhancer of ATP2B4 mediates red blood cell hydration and malaria susceptibility [genotype]

Few genotype-phenotype associations identified by genome-wide association studies (GWAS) have been defined mechanistically, precluding thorough assessment of their impact on human health. We conducted an expression quantitative trait loci (eQTL) mapping analysis in human erythroblasts and found erythroid-specific eQTLs for ATP2B4, the main calcium ATPase of red blood cells (RBC). The same SNPs were previously associated with mean corpuscular hemoglobin concentration (MCHC) and susceptibility to severe malaria infection. We showed that Atp2b4-/- mice demonstrate increased MCHC, confirming ATP2B4 as the causal gene at this GWAS locus. Using CRISPR-Cas9, we fine-mapped the genetic signal to an erythroid-specific enhancer bound by GATA1 and TAL1. These results illustrate the importance to combine transcriptome, epigenome, and genome editing approaches in phenotype-relevant cells to characterize non-coding regulatory elements associated with human complex diseases and traits. Our studies suggest ATP2B4 as a potential target to modulate RBC hydration in erythroid disorders and malaria infection. Genotypes of fetal (N=12) and adult (N=12) erythroblasts were obtained using the HumanOmniExpress-12 v1.1 BeadChip array