RAG1 and combined immunodeficiency: Furthermore, four compound heterozygous RAG1 patients, classified as SCID (PID-6), OS (PID-9), and CID (PID-19, PID-21), shared the same p.R624H mutation, with almost absent recombination activity, in combination with the p.R405G, p.Y728H, and p.R561H respectively.