One is genome-wide association studies (GWASs), which revealed that loss-of-function single-nucleotide polymorphisms (SNP) in the PTPN2 gene confer a predisposition for the onset of inflammatory bowel disease and the development of immune disorders (e.g., Crohn’s disease, Type 1 diabetes, rheumatoid arthritis, and celiac disease) [11,12]. This evidence concerns the gene PTPN2 and inflammatory bowel disease.