Secondly, and as mentioned above, both affected loci exhibit RAN translation potential, leading to the production of toxic polyglycine, polyalanine and polyarginine containing proteins by CGG expansion in the PM range in FMR1 [28,132,173], and polyalanine- and polyserine-containing proteins by CTG expansions in DM1-affected cells [127,174]. This evidence concerns the gene FMR1 and myotonic dystrophy type 1.