We have also analysed available online data from Ambry genetics commercial testing (https://www.ambrygen.com/providers/resources/prevalence-tool, accessed 29/08/2020).23 While it is not possible to assess the level of pretesting for TP53, and BRCA1/2 or the presence of a Li Fraumeni family history, there is a clear upward trend of prevalence of BRCA1 and BRCA2 PVs with reducing age at breast cancer until 26 years of age (online supplemental table 3). This evidence concerns the gene TP53 and breast cancer.