Recombination activity of mutant RAG2 proteins. A, Graphic representation of the recombination activity of various RAG2 mutations according to their position in different domains of the RAG2 protein (core domain: amino acids 1–383; plant homology domain [PHD]: amino acids 414–487). Solid circles identify nonsense mutations, and triangles represent missense mutations. Means ± SEMs are shown to illustrate recombination activity. For each RAG2 variant, the assay was performed in triplicates. B, Frequency of pathogenic mutations (defined as recombination activity <80% WT-hRAG2) per amino acid length of various domains of the hRAG2 protein. C, Recombination activity (expressed as percentage of the activity of WT-hRAG2) of nonsense and missense hRAG2 mutations. Bars represent means ± SEMs. Statistical analysis was performed with the Mann-Whitney test. D, Recombination activity (expressed as percentage of the activity of WT-hRAG2) of missense mutations affecting the PHD and non-PHD domains of the hRAG2 protein. Bars represent means 6 SEMs. Statistical analysis was performed with the Mann-Whitney test. n.s., Not significant.