RAG1 and severe combined immunodeficiency: Similarly, the p.S330LfsTer15 mutation is found in PID-4 falls in the RING domain of RAG1, determining the absence of recombination activity by affecting protein subcellular localization or decreasing chromatin accessibility of the RAG complex [34, 35]; however, in this patient, the resulting truncated protein is the most evident cause of SCID phenotype.