Combined GWAS and transcriptome-wide association tests have identified several genetic loci that may be relevant in asthma, such as the chromosome 17q locus, HLA, IL-6, interferon regulatory factor 4 (IRF4), chemokine (C-C motif) ligand 20 (CCL20), mucin 5AC (MUC5AC), fatty acid desaturase 2 (FADS2), T-box transcription factor 21 (TBX21), runt-related transcription factor 1 (RUNX1), and cytokine and chemokine receptors and signaling molecules (Pividori et al., 2019; Vercelli and Bleecker, 2019). This evidence concerns the gene CCL20 and asthma.