Proposed roles for long noncoding RNAs (lncRNAs) in Duchenne muscular dystrophy. (A) In the nucleus, sense and antisense transcription from intronic sequences of the dystrophin (DMD) gene gives rise to lncRNAs that play a repressive effect at specific DMD promoters. (B) In the cytoplasm, the muscle specific lncRNA linc-MD1 acts as a competitive endogenous RNA (ceRNA) by sequestering miRNAs away from their target mRNAs. Linc-MD1 contributes to muscle differentiation by sponging miRNA-135 and -133, and thus promoting the expression of MEF2C and MAML1. Linc-MD1 is strongly reduced in muscle cells from DMD patients.