We wish to reply to the Letter to the Editor written by Machado and Vaz [1] concerning our recently published article on the c.156_157insAlu BRCA2 founder mutation [2], first discovered by Teugels et al. [3] in a Portuguese patient living in Belgium. That letter has several misstatements about our and others’ work that must not remain unchallenged. Machado and Vaz suggest in their letter [1] that we diagnose the c.156_157insAlu BRCA2 mutation by subjective evaluation of band intensities after RT-PCR. We think that it is clear in our paper [2], under the subheading ‘‘Screening for the c.156_157insAlu BRCA2 mutation’’, that we screen for this mutation by using two independent PCRs, one for exon 3 amplification and another specific for the Alu rearrangement. Using this strategy, in positive cases we expect two bands in the first PCR (one band if negative) and one band in the second PCR (none if negative). The second PCR helps to control the first PCR for eventual problems with preferential amplification of the shorter fragment (the normal), whereas the first PCR controls for eventual absence of amplification in the second PCR. This strategy of two independent PCRs (which differs from the nested PCR approach used by Machado et al. [4]), followed by sequencing of the genomic fragments in positive cases, allows the unambiguous detection of the c.156_157insAlu BRCA2 mutation. In the Results section of our article [2], the molecular diagnosis of families with the c.156_157insAlu BRCA2 mutation is also described under the separate subheading ‘‘Detection of the c.156_157insAlu BRCA2 mutation’’, whereas any mention to RT-PCR data appears under the subheading ‘‘Analysis of RNA transcripts’’. Therefore, the reason why we performed RT-PCR with primers located in exons 1 and 6 was not to confirm the mutation, but to deliberately be able to compare the physiologic alternative splice lacking exon 3 in controls with the effect of the exon 3 Alu insertion in carriers. Taking advantage of a known polymorphism in BRCA2 exon 2 (previously reported as c.-25G[A [2, 5, 6], but described as c.-26G[A according to the recommendations of the Human Genome Variation Society [7], we clearly demonstrated in Fig. 1 of our paper [2] the preferential production of the transcript without exon 3 by the allele with the Alu insertion and its (presumably residual) production by both alleles in non-carriers. Machado and Vaz [1] state that RT-PCR must be used to confirm the c.156_157insAlu BRCA2 mutation in each patient and that a reliable confirmation of this rearrangement must be done using the primers in exons 2 and 10 first described by Nordling et al. [8]. Both these claims are unfounded for the following reasons. First, it is not necessary to confirm one given mutation at the RNA level in every new patient once its pathogenic nature is well established, as it is now the case for this BRCA2 rearrangement. Second, Machado and Vaz claim [1] that these primers amplify specifically the transcript produced from the allele with the Alu insertion, and not the ubiquitous alternative splice transcript, allegedly because only the former transcript includes at least the first part of BRCA2 exon 10 [1]. They present no data to support this assumption nor do they exist in the literature. In fact, Zou et al. [9] have shown that the full length transcript and the ubiquitous alternative splice differ only by the lack of exon 3 in the latter, so exon 10 does not distinguish them. Additionally, the forward primer described by Nordling A. Peixoto C. Santos P. Rocha P. Pinto S. Bizarro M. R. Teixeira (&) Department of Genetics, Portuguese Oncology Institute, Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto, Portugal e-mail: manuel.teixeira@ipoporto.min-saude.pt