Importantly, those revised criteria also recommend to rule out profound T lymph cell deficiencies and clearly define the minimal age-matched T cell absolute count to preclude severe combined and combined immunodeficiencies (SCID and CID, respectively), such as CD40 ligand (CD40L) [7] and serine-threonine-kinase-4 (STK4) [8] deficiencies or the immunodeficiency, centromeric instability, and facial anomalies syndrome (ICF) [9]. Here, STK4 is linked to combined immunodeficiency.