The severe combined immunodeficiency (SCID) is a loss-of-function mutation, which affects the protein kinase, DNA-activated catalytic polypeptide (PRKDC), leading to an inefficient DNA non-homologous end joining repair that is required for T cell and B cell receptor rearrangement, resulting in a lack of mature T and B cells (Blunt et al., 1995) (Bosma et al., 1983) (Kirchgessner et al., 1995) (Mosier et al., 1988). Here, PRKDC is linked to severe combined immunodeficiency.