Gene variation and reversion probability in PIDs. (A) CD247 sequence analysis of samples from the patient and controls revealed high genetic variability. (B) Freshly isolated PBMCs from a CD3γ^−/− patient and control were stained and analyzed by flow cytometry. (C-E) Analysis of data from the 1000 Genomes Project revealed no differences in the occurrence of synonymous mutations (C), but an increased frequency of missense mutations (D) in the coding region (E) was observed for PID genes where reversion has been described compared with PID genes with no reversion described or control genes. CD247 and WASp are specifically indicated in panels C and D. Statistical significance was calculated using a 1-way analysis of variance for synonymous and missense variation rates and a 2-way analysis of variance for variation vs gene region analysis comparing the 3 different groups of genes (**P < .01; ***P < .001; n.s., P > .05).