FAS and inborn error of immunity: Indeed, defective FASL-induced lymphocyte apoptosis underlies a group of primary immunodeficiencies (PIDs) denoted as autoimmune lymphoproliferative syndrome (ALPS) and our screen with FASL retrieved SLC39A7 amongst genes previously identified in ALPS- and ALPS-like PIDs such as FAS, FADD, and CASP8 (Supplementary Figures 4b) [67].