Neurofibromatosis type 1 (NF1) is a genetic condition characterized by increased risk of developing tumors, as well as various other physical and neurological manifestations. NF1 women were previously reported to have an increased risk of breast cancer. There are different genetic variants causing NF1: in ~5-10% of patients, large deletions of the entire NF1 locus are identified, while most NF1 patients have intragenic mutations. Previous studies have not identified breast cancer in women with large NF1 deletions. In this study, we show that women with large NF1 deletions may also be at risk of breast cancer. This should have major consequences in the close monitoring of NF1-deleted patients for the early detection of breast cancers. (By Prof Eric Pasmant, https://jmg.bmj.com/content/early/2023/12/21/jmg-2023-109682 )