XIAP and Immunodeficiency: Since no diagnostic details are given, the exclusion of combined immune deficiencies involving T-cell immunity as well as B-cell failure (5), or known mutations in monogenic disease (e.g. CTLA4, LRBA, KMT2D, XIAP, RAG1, NFKB1) (34, 39, 51–57, 63) is unclear.