Exon deletions and duplications in BRCA1 detected by semiquantitative PCR

Large rearrangements have recently been identified in the BRCA1 gene. Inclu sion of a method for identifying such rearrangements should now be a prereq uisite for providing a comprehensive mutation detection strategy. We have d eveloped a semiquantitative PCR-based fluorescent assay for the detection o f previously identified deletions. This method avoids the need for long PCR or Southern blotting and is suitable for large-scale epidemiological studi es. The assay was used to screen 44 high-risk families within the U.K. York shire Health Region. No deletions were detected, but five cases (11%) with an apparent duplication of exon 13 in BRCA1 were identified. The presence o f this mutation was confirmed by long PCR. Further developments include ext ending the assay to include all exons of BRCA1.