Transcription-dependent R-loops can also alter the expression levels of genes involved in various disorders. For example, it has been reported that R-loops cause gene silencing at expanded trinucleotide repeats at FXN and FMR1 genes consequently proving an R-loop role in Friedreich's ataxia and X fragile syndrome. Anyway, transcription-mediated R-loop harmful effects are mostly related to the replication process.