During V(D)J recombination, DNA double-strand breaks (DSBs) near the V, D, and J coding gene segments and recombination signal sequences [6] are introduced by the recombination activating gene (RAG1 and RAG2) complex, and mutations in these two genes can lead to severe combined immunodeficiency (SCID) [7]. This evidence concerns the gene RAG1 and severe combined immunodeficiency.