The eight tagSNPs encompassing IDO1/IDO2 loci have been successfully genotyped in the CF cohort with genotyping rate above 90%, not showing significant deviation from HWE and having MAFs comparable to the ones reported for the European population of the 1,000 Genomes Consortium (26) (Supplementary Table 1). This evidence concerns the gene IDO1 and cystic fibrosis.