APDS, ALPS, CVID, SIgAD, STAT1 GOF, STAT3 GOF, DGS, IPEX, CTLA‐4 haploinsufficiency and deficiency of LRBA, WAS, dominant‐negative defects in CARD11, ICOS deficiency, PNP deficiency, SCID. This evidence concerns the gene ICOS and severe combined immunodeficiency.