BARD1 and breast cancer: Case–control analyses have shown BARD1 loss of function variants to be associated with a low (< 2-fold) to moderate (> 2-fold) increase in risk of breast cancer (Couch et al., 2017; Kurian et al., 2017; Slavin et al., 2017) and up to five-fold increase in risk of triple negative breast cancer (Shimelis et al., 2018).