The 17q21 locus harbours a dense haploblock of 136 SNPs in tight linkage disequilibrium that overlap six gene loci: IKZF3, ZPBP2, GSDMB, ORMDL3, LRRC3C and GSDMA1, 23, of which the expression of two genes (ORMDL3 and GSDMB) has been shown to be modestly affected by the asthma-risk SNPs in the locus24, 25, 26. The gene discussed is IKZF3; the disease is asthma.