In situ hybridization and translocation breakpoint mapping

Abstract
Using a combination of banding techniques, we examined two atypical 21;22 translocations, 46, XX or XY, t(21;22)(p11;q11). In situ chromosomal hybridization of a probe for the constant region of the lambda light chain locus demonstrated that the 22q11 breakpoints of both rearrangements were proximal to the Cλ gene cluster. These studies permitted us to distinguish the 22q11 breakpoints of these translocations from the breakpoint of the 22q — chromosome of chronic myelogenous leukemia.