Spectrum of Vδ2-Jα rearrangements in childhood precursor-B–ALL. (A) Bar diagram summarizing the usage of Jα segments in Vδ2-Jα rearrangements in precursor-B–ALL. (B) Schematic diagram of the Vδ2 gene segment joined to the Jα29 gene segment via a junctional region. The presented Vδ2-Jα29 junctional region sequences are derived from precursor-B–ALL and illustrate the deletion of nucleotides from the germline sequences as well as the size and composition of the junctional regions. Dδ gene segments and inserted nucleotides are indicated by uppercase and small uppercase letters, respectively. (C) Multiplex heteroduplex PCR analysis with the Vδ2 primer in combination with 8 Jα primers (mix 3) showed clonal Vδ2-Jα homoduplexes (ho) in all samples tested. Sequence analysis (B) showed that all these rearrangements involved the Jα29 gene segment. The presence of heteroduplexes (he) in cases 5199, 5504, and 5609 indicated the presence of double Vδ2-Jα29 rearrangements.