RUNX3 and selective IgA deficiency disease: Serum IgA production has a strong, reproducible association with RUNX3 and our cFDR analysis elevated to significance an association of SIgAD with the same locus: the sole genome-wide significant SNP lay in the exonic sequence of the obscure lncRNA RP11-84D1.2 and within a candidate cis-regulatory element.