Partial trisomy 7p defined by analysis of a complex chromosome rearrangement using a BAC clone panel

Purpose: To illustrate the use of bacterial artificial chromosome (BAC) clo ne panels for molecular cytogenetic analysis of complex chromosome rearrang ements (CCRs). Methods: High resolution cytogenetics followed by fluorescen ce in situ hybridization (FISH) analysis using chromosome band-specific BAC probes, in addition to commercially available probes. Results: High resolu tion cytogenetics in conjunction with FISH using commercially available pro bes proved inadequate to resolve problems in characterizing a balanced CCR in the mother of a patient who had inherited an unbalanced form of the CCR. Accurate interpretation of the CCR and the unbalanced rearrangement in the patient as trisomy 7p12.2 --> p21.3 was accomplished only through use of t he BAC clone panel. Conclusion: Use of BAC clone panels can enhance the pow er of FISH analysis in defining chromosome rearrangements that cannot be re solved by high resolution chromosome analysis.