We report here results from a GWAS of opioid criterion count in EA subjects. There was a GWS association of an RGMA variant, rs12442183, in Yale-Penn 1. There was nominally significant evidence for association of the same variant in both Yale-Penn 2 and Yale-Penn 3, and when all EA samples (including SAGE, where no evidence of the association was obtained) were meta-analyzed together, the significance of the association finding increased. Because the minor allele frequency of rs12442183 was similar for the EA and AA populations, we further evaluated the association of rs12442183 with OD in the Yale-Penn AA sample. The nominally significant association in the AA meta-analysis (n=2014, meta-P=3×10-3) further supports the association. (AA replication of results from EA samples is not universally applicable, but in this case, we found evidence that we believe is of value.) Cis-eQTL analysis of RGMA in brain showed the rs12442183*T risk allele to be associated with higher expression of RGMA transcript variant 4 (encoding RGMa isoform 3) in frontal cortex. This observation is consistent with the upregulation of Rgma in C57BL/J6 mice treated with
