We were able to identify mtDNA deletions (>10% deleted mtDNA) (Grady et al., 2014) in a minority of our samples (5 out of 36, or 13%, PMS cases and 9 out of 43, or 20%, controls), indicating that ccf-mtDNA is intact in the majority of samples (Supplementary Fig. 2). This evidence concerns the gene PITX1 and premenstrual tension.