Analysis of exon 6 of the PIG-A gene before BMT and after relapse. (A) Heteroduplex Analysis (HA); Two extra bands (235 bp, mutant homoduplex; H, heteroduplex) in patient MSK13 are clearly observed after relapse (lane 4) but not before BMT (lane 2). (B) Single-Strand Conformation Analysis (SSCA). Along with double-stranded fragments DNA, an altered electrophoretic mobility (shift) of the single-stranded DNA (SS) is only present after relapse (lane 4). Normal controls (lanes 1, 3, 5); normal homoduplex, 201 bp.