ITPR3 and Immunodeficiency: We systematically reviewed 11 recently reported cases of ITPR3-mutated patients with immunodeficiency manifestations across three publications, and combined them with our two cases reported here plus an additional patient (designated P3, see Supplementary Materials for clinical history) carrying the pathogenic ITPR3 c.7570C>T, p.(Arg2524Cys) variant identified from our internal database, totaling 14 cases (11–13).