A variant of RAG1 gene identified in severe combined immunodeficiency: a case report

BACKGROUND: The recombination-activating gene 1 (RAG1) protein is essential for the V (variable)-D (diversity)-J (joining) recombination process. Mutations in RAG1 have been reported to be associated with several types of immune disorders. Typical clinical features driven by RAG1 variants include persistent infections, severe lymphopenia, and decreased immunoglobulin levels . CASE PRESENTATION: In this study, a 2-month-24-days-old infant with recurrent fever was admitted to our hospital with multiple infections and absence of T and B lymphocytes. The infant was diagnosed with severe combined immunodeficiency (SCID). A homozygous variation c.2147G>A (NM_000448.2: exonme2: c.2147G>A (p.Arg716Gln)) was identified in the RAG1 gene using whole-exome sequencing and Sanger sequencing. The predicted 3D structure of variant RAG1 indicated altered protein stability. Additionally, decreased expression of variant RAG1 gene was detected at both the mRNA and protein levels. CONCLUSIONS: Our study identified a novel homozygous variant in RAG1 gene that causes SCID. This finding expands the variant spectrum of RAG1 in SCID and provides further evidence for the clinical diagnosis of SCID. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03822-0.