CELF1 and myotonic dystrophy type 1: In this regard, we recently identified a set of mRNAs altered in the brains of CUGBP1-S302A-KI mice (own unpublished data) in which accumulation of inactive CUGBP1 (CUGBP1REP) mimicking increased amounts of CUGBP1REP in DM1 tissues causes severe brain atrophy [27].