Muscleblind-like splicing regulator 1 (MBNL1) is sequestered into RNA foci containing expanded ATXN1, ATXN3, and ATXN7 transcripts in SCA1, SCA3/MJD, and SCA7 patient fibroblasts, respectively [137, 138]. The gene discussed is ATXN3; the disease is Machado-Joseph disease.