Novel RAG2 Mutation in a Patient with Leaky Severe Combined Immunodeficiency

T and B lymphocytes development and function are highly dependent on Recombination Activating Genes (RAG) 1 and 2. RAG mutations result in different degree of T and B cell impaired function, broad clinical manifestations, and immunological manifestations. Pathogenic mutations cause severe combined immunodeficiency (SCID) phenotype, while hypomorphic mutations are responsible for leaky or partial SCID. Here, we described a 4-year-old girl who had a persistent diarrhea, recurrent infection and vomiting. Although physicians were suspicious about autoimmune enteropathy, her molecular report showed a homozygous and novel RAG2 mutation in its core domain. The number of CD4 T cells and IgA level were lower than normal ranges. Lack of IgA brought about different GI complications. Our patient died finally because of the liver and gallbladder failure.