PRKDC and severe combined immunodeficiency: Besides, DNA-PKcs involves in other cellular processes such as replication stress response,219 transcription,220 telomere maintenance & capping221,222 and innate immunity.223 Strikingly, deficiencies in DNA-PKcs encoding gene PRKDC dampen T and B cell development and lead to severe combined immunodeficiency (SCID) in mice.224 With its versatile roles in physiological processes, DNA-PKcs may be essential to certain normal tissues.