The closest paralogue to PTP1B is PTPN2 (also known as TC-PTP) encoded by PTPN2, with shared identity in their catalytic and substrate recognition domains manifesting as a common activity for some substrates.9 Notably, human germline heterozygous and biallelic variants in PTPN2, leading to haploinsufficiency or loss-of-function (LOF) of the encoded protein, have recently been associated with autoimmune enteropathy,10,11 immunodeficiency,12 and systemic autoimmunity including systemic lupus erythematosus and cytopenias.12,13. Here, PTPN2 is linked to immune system disorder.