In DM1, downregulation of these genes by epigenetic changes, such as hypermethylation may participate in some clinical features including cataracts, muscle defects or cardiac conduction abnormalities as observed in DMPK, SIX5 or DMWD knockdown mouse models [54,55,56,57,58,59]. Here, SIX5 is linked to myotonic dystrophy type 1.