CAG repeats in transcripts are similar to CUG repeats in their interaction with the splicing regulator MBNL1 (34,36), whose sequestration by CUG tracts causes splicing aberrations leading to DM1 (28,37) and spinocerebellar ataxia type 8 (SCA8) (38). Here, MBNL1 is linked to spinocerebellar ataxia type 8.