A deletion/insertion mutation in the BRCA2 gene in a breast cancer family: A possible role of the Alu ‐polyA tail in the evolution of the deletion

Patients with breast and/or ovarian cancer were screened for gross rearrangements in the BRCA2 gene by Southern hybridization, with exon 10 and a fragment of exon 11 used as probes. One breast cancer patient with a positive family history had a 6.2‐kb deletion including exons 12 and 13. The deletion breakpoint in intron 11 was in the 3′ polyA tail of an Alu element, where a track of ≈60 adenine nucleotide residues was inserted. Expansion of the Alu ‐polyA tail may have resulted from polymerase slippage during replication, representing a novel mechanism in which Alu elements mediate deletion/insertion mutations. © 2001 Wiley‐Liss, Inc.