To date, there are some studies related to IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780) gene SNPs and risk of tuberculosis (TB), gastric cancer, rheumatoid arthritis (RA), intestinal bowel disease (IBD), Crohn's disease (CD), ulcerative colitis (UC), and others [14]. Here, IL17A is linked to Crohn disease.