In X-SCID, T and NK cells are either absent or significantly diminished, while B cells exhibit functional impairments, with their numbers being normal or increased.1,7 Another gene associated with SCID is RAG1, which plays a crucial role in adaptive immunity by facilitating V(D)J recombination in developing lymphocytes.3 The RAG recombinase (RAG1/2) randomly combines variable (V), diversity (D), and joining (J) gene segments to generate a V(D)J exon, which encodes the variable region of T cell receptors and antibodies. Here, RAG1 is linked to severe combined immunodeficiency.