Omenn Syndrome (RAG2-Related) (RAG2)

Omenn syndrome (RAG2-related) is an autosomal recessive immunodeficiency disorder caused by pathogenic variants in the gene RAG2. While it has been reported in individuals worldwide, it has an increased frequency in Sephardic Jewish individuals from Iraq. Age of onset is in the first months of life and clinical features include a red rash and an enlarged liver, spleen and lymph nodes. Decreased B-cell production results in increased frequency of infections, which worsen in severity over time. As the disease is fatal if not treated, patients typically require bone marrow transplants or stem cell transplants. Death may occur due to transplant complications, but a successful transplant is curative. Outcome is improved if diagnosis occurs early in life. No genotype-phenotype correlation is known.

For information about carrier frequency and residual risk, please see the residual risk table.