RAG1/2,DCLRE1C,PRKDC,NHEJ1, andLIG4 result in isolated non-syndromic combined immunodeficiency (CID, due to low-T low-B CID) while defects in other genes cause syndromic combined immunodeficiencies (due to the additional roles of these genes in non-immune cells) [83,106] . The gene discussed is PRKDC; the disease is severe combined immunodeficiency.