Characterization of Sμ–Sγ junctions in Artemis-deficient patients. (A) PCR amplification of Sμ–Sγ1, Sμ–Sγ2, and Sμ–Sγ3 fragments. Three experiments were performed and a representative example is shown in the figure. (B) Sμ–Sγ–Sγ sequential switching in AKE, showing the actual sequences of the Sμ–Sγ and Sγ–Sγ junctions.