Inherited immune disorders
RAG2 deficiency
RAG2 deficiency impairs the DNA rearrangement needed to build T- and B-cell receptors. Severe loss of function can cause SCID; partial function can cause Omenn syndrome or later combined immunodeficiency with infection and immune dysregulation.
Other names and abbreviations
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
Where transplant fits
Allogeneic transplantation can provide functioning donor immune cells. A suitable related or unrelated donor may be used. The person’s actual immune phenotype, infections and organ health guide timing and conditioning.
Treatment depends on the exact diagnosis, disease stage, prior treatment and the person’s health. These categories are not estimates of donor demand.
Treatment at a glance
- Who it affects
- Can be identified in infancy or later childhood and adulthood, depending on the variants and remaining protein function.
- Other treatment options
- Infection prevention and treatment, immunoglobulin support and management of inflammation or autoimmunity may be needed before transplantation.
- Cells used for transplantation
- When transplantation is appropriate, the graft contains blood-forming stem cells from a suitable donor. Bone marrow, peripheral blood or cord blood may be selected according to the condition and transplant protocol.
Why the details matter
Neither the gene name nor a measurable lymphocyte count defines severity by itself. Omenn syndrome is one possible presentation, not a synonym for every RAG deficiency.
Questions to bring to your care team
What is the exact diagnosis or subtype? What is the goal of each treatment option? If transplant is being considered, why does it fit this situation, which cells would be used and what are the alternatives?
Sources and further reading
- Omenn syndrome
MedlinePlus Genetics, US National Library of Medicine · Accessed 2026-09-05 - Guidelines for hematopoietic stem cell transplantation for inborn errors of immunity
EBMT / ESID Inborn Errors Working Party · 2021 - Inborn Errors of Immunity
EBMT Handbook · 2024-04-11
Understanding can become action.
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