XIAP and Arthritis: In the case of TNFR-associated periodic syndrome (TRAPs), XIAP deficiency (i.e., hemophagocytic lymphohistiocytosis), haploinsufficiency in A20 (HA20), LUBAC deficiency, otulipenia, and biallelic RIPK1 deficiency common overlapping clinical manifestations include recurrent fever and infection, arthritis and arthralgia/myalgia (i.e., joint and musculoskeletal pain), skin lesions, and intestinal inflammation and/or diarrhoea, as well as on occasion hepatosplenomegaly [63,98,103,104,105,106,107,108].