ATP12A and Meconium ileus: To determine whether gene expression variation at the three genome-wide significant loci (SLC6A14, SLC26A9 and ATP12A) influence meconium ileus risk and in which tissue(s), we used data from the GTEx v7 (accessed on Oct 1, 2018) [23] and considered the enhancer and promoter states from the Regulatory Regions Map (Reg2map; see Web Resources in Material and Methods) [24, 25].