Combined Immunodeficiency Due to Partial Rag1 Deficiency, also known as combined immunodeficiency with expansion of gamma delta t cells, is related to alpha/beta t-cell lymphopenia with gamma/delta t-cell expansion, severe cytomegalovirus infection, and autoimmunity. An important gene associated with Combined Immunodeficiency Due to Partial Rag1 Deficiency is RAG1 (Recombination Activating 1). Affiliated tissues include t cells, and related phenotypes are splenomegaly and immunodeficiency