PTPN2 and Immunodeficiency: In search of immunogenetic indicators of CVID-related IBD-like colitis, pathogenic variants in several genes linked to immune dysregulation and immunodeficiency, such as CTLA, PIK3CD associated with activated phosphoinositide 3-kinase delta syndrome 1 (APDS1), PIK3R1 (APDS2), TNFRSF13B (TACI), NFKB1, NFKB2, and protein tyrosine phosphatase, non-receptor type 2 (PTPN2) [60].