Hypomorphic RAG variants can retain partial recombination activity and result in a distinct phenotype of combined immunodeficiency with granuloma and/or autoimmunity (CID-G/A), as well as other milder forms, such as antibody deficiency, Idiopathic CD4+ T lymphopenia  or vasculitis. RAG deficiency can be measured by in vitro quantification of recombination activity. 71 RAG1 and 39 RAG2 variants have been functionally assayed to date (2019) (less than 10% of the potential point mutations that may cause disease).
Hypomorphic RAG variants can retain partial recombination activity, leading to a distinct phenotype of combined immunodeficiency with granuloma and/or autoimmunity (CID-G/A), as well as other milder forms like antibody deficiency, Idiopathic CD4+ T lymphopenia or vasculitis.