While epigenetic modifications are known as a gene-disrupting mechanism in some well-known TREs [12, 35], such as CGG repeat expansions in FMR1, we found that CG-containing motifs are uncommon in the tandem repeats expanded in schizophrenia (Supplementary Table S1), and in fact are significantly less common than the unexpanded tandem repeats or the known pathogenic repeats (Supplementary Fig. S2). Here, FMR1 is linked to schizophrenia.