Inherited immune disorders
RAG2 deficiency
Also called: RAG2-SCID · T-B-NK+ SCID · Omenn syndrome · SCID · primary immunodeficiency · RAG2-associated severe combined immunodeficiency · Severe combined immunodeficiency due to complete RAG2 deficiency · Omenn syndrome due to RAG2 deficiency
What a donor has to do with this
For some people with this condition, a transplant using blood stem cells from an unrelated donor is part of the treatment guidelines. When a transplant is the right route and no one in the family matches, that donor comes from a registry. Not everyone with this condition has a transplant, and many never need one.
This is our reading of published transplant guidelines for this condition, not a measurement of how many people need a donor. Where a source actually counted donors, the figure and the people it counted are shown further down. Where none did, we say so rather than estimate.
What the evidence says
- Who it affects
- Typical onset/diagnosis: complete RAG2 deficiency presents neonatally or in infancy, while hypomorphic disease can present in adolescence. Evidence: international review and an 82-patient Slavic cohort (2020), in which 15 patients (18.3%) had RAG2 variants; no markedly enriched population was identified.
- Treatments other than a transplant
- Immunoglobulin replacement and antimicrobial prophylaxis — supportive/bridge to HCT — multiple regions — Does not restore V(D)J recombination; RAG2 gene correction remains investigational.
- If a transplant is used, the cells come from
- bone marrow: used in opened IEI transplant guidance; disease-specific share was not reported; mobilized peripheral blood stem cells: used in opened IEI transplant guidance; disease-specific share was not reported; umbilical cord blood: used as an alternative in opened IEI transplant guidance; disease-specific share was not reported; dominance: no dominant graft source was reported in the opened disease-specific sources
- How often the donor was unrelated
- Not reported. No source we could read states this for this condition, so we do not give a number. An estimate here would be a guess dressed as evidence.
Where this gets complicated
Hypomorphic RAG2 variants can cause Omenn syndrome, leaky SCID, or later combined immunodeficiency rather than classic infantile T-B-NK+ SCID.; The 2019 Brazilian single-patient report described a 14-year-old girl evaluated in São Paulo with 16% relative recombinase activity; HCT decisions remain individualized.
“Hematopoietic stem cell transplantation is the only curative treatment available for RAG deficiencies up to date”
It describes what teams consider in general. It cannot say what applies to any one person. Read the source.
People with this condition need donors
Joining a registry is a cheek swab and a short health form. You are contacted only if you turn out to be a possible match for someone, and you can ask questions and decline before anything else happens.
Related conditions
Others in inherited immune disorders. They are genuinely different diseases with different treatments — the group name is not a diagnosis.
Where this came from
- Severe combined immunodeficiency, autosomal recessive, T-cell negative, B-cell negative, NK-cell positive — NIH NCATS GARD, updated 2026-06
- Guidelines for hematopoietic stem cell transplantation for inborn errors of immunity — EBMT/ESID Inborn Errors Working Party, 2021
- Innovative Cell-Based Therapies and Conditioning to Cure RAG Deficiency — Frontiers in Immunology, 2020-11-19
- The Clinical and Genetic Spectrum of 82 Patients With RAG Deficiency Including a Founder Variant in Slavic Countries — Frontiers in Immunology, 2020
- Combined Immunodeficiency With Late-Onset Progressive Hypogammaglobulinemia and Normal B Cell Count in a Patient With RAG2 Deficiency — Frontiers in Pediatrics, 2019