Allelic imbalance of BRCA1 transcript in the IVS20 12-bp insertion carrier.

One of the unclassified variants of the BRCA1 gene which has drawn considerable attention in recent years is the 12-bp insertion/duplication in intron 20. In this report, we show that a contribution from one chromosome cannot be detected in the BRCA1 transcript of the 12 bp insertion carrier. We also demonstrate here that the single transcript variant we observe by cDNA analysis originates from the same BRCA1 allele that harbours the 12-bp insertion. Hum Mutat 16:371, 2000.