BRCA1 and Miyoshi myopathy: If we exclude Signature 3 from our analysis, none of the 30 MM samples would be classified as HRD, as they do not appear to be enriched with the patterns that are typical of the BRCA1/BRCA2-type of HRD: there is a low proportion of microhomology-mediated type of small deletions, the HRD-LOH index46 is low, and there is a limited number of 1–100 Kb deletions (Rearrangement Signature 5) and 1–100 Kb tandem duplications (Rearrangement Signature 3) (Fig. 2a, Supplementary Figs. 5 and 6).