A study examining the genetic overlap between the datasets of primary immune‐deficiencies and inflammatory diseases such as Crohn's disease, ulcerative colitis, very early‐onset monogenic IBD, and multiple sclerosis; has identified several intersecting loci including the one that contains RTEL1 and proposed that the inactivating variants of these genes may cause immunodeficiency, while variants causing their subtler modulation may contribute to chronic inflammation.62 This evidence concerns the gene RTEL1 and Immunodeficiency.