CCL21 and cystic fibrosis: Four genes of the SLC family, including SLC11A1 [42, 70], SLC26A9 [16, 18, 19, 37, 42, 70, 84], SLC6A14 [7, 18, 19, 37, 40, 42, 70], and SLC9A3 [17, 19, 30, 37, 42, 70], have been identified as GMs of CF, influencing both positively and negatively MI, PI, CFRD, lung disease severity, the age of onset of P. aeruginosa, osteoporosis, lower age of onset of digestive symptoms, and nutritional status.