We measured expression of the genes mapping closest to our lead SNPs (in DGKB/TMEM195, ADCY5, MADD, its neighboring gene SLC39A13 [a member of a family of zinc transporters mapping ~45 kb from the MADD lead SNP], ADRA2A, FADS1, CRY2, SLC2A2, GLIS3, PROX1 and FAM148B) in human pancreas and other metabolically relevant tissues (Supplementary Figure 4a). While there was evidence of expression in human islets for nearly all genes tested (with the sole exception of TMEM195), we found that DGKB and MADD were most strongly expressed in brain, SLC2A2, FADS1, TMEM195 and PROX1 in liver and ADCY5 in heart, while SLC39A13, ADRA2A and CRY2 were broadly expressed. Strikingly, FAM148B was highly expressed in the whole pancreas with lower levels in isolated islets, suggesting that it is also present in exocrine cells. A duplicate experiment in a different laboratory obtained similar results (Supplementary Figure 4b). We further examined expression of these transcripts in flow-sorted human β-cells from two separate individuals and documented β-cell expression for all but TMEM195, with SLC39A13, CRY2, GLIS3 and PROX1 being particularly highly expressed in these cells (Supplementary
