Introduction Lamin A/C intermediate filaments, encoded by LMNA gene, are one of the components of the nuclear lamina, a protein meshwork underlying the inner nuclear envelope. They play a key role in nuclear resistance to mechanical stress, thus maintaining cell integrity, and they also regulate gene expression through interaction with chromatin, nuclear histones and transcription factors. It has been reported that miRNA transcriptome is altered in patients with striated muscle laminopathies, a group of disorders due to mutations in lamin A/C, and in the presence of nuclear envelope abnormality, indicating that nuclear lamina might also be involved in miRNA regulation. Results Here we show that miRNA-processing pathway is dysregulated in myotubes from our mouse model for LMNA-related Congenital Muscular Dystrophy (L-CMD) KI-LmnaK32del/K32del, but not in myotubes from our mouse model for Emery-Dreifuss Muscular Dystrophy (EDMD) KI-LmnaH222P/H222P. We found that expression of miR-133a-3p and miR-206-3p expression is altered in KI-LmnaK32del/K32del myotubes. In order to determine which step of the miRNA-processing pathway is affected, we compared the efficacy of shRNA and siRNA knockdown that enter to the miRNA pathway after DROSHA-DGCR8 complex or after DICER, respectively. While siRNA knockdown was efficient, shRNA-mediated knockdown was not, indicating a defect in upstream miRNA-processing pathway in cells LmnaK32del/K32del. Interestingly, overexpression of wild-type lamin A into LmnaK32del/K32del myotubes resulted in an improvement in shRNA efficiency. Conclusions Overall, these data suggest that lamin A/C might have an important role in miRNA regulation.