Limb Girdle Muscular Dystrophy D2 (LGMDD2) is a rare neuromuscular disorder caused by a heterozygous mutation in the termination codon of the TNPO3 gene and a mainly atrophic phenotype of patients. This gene encodes for Transportin-3 (TNPO3), an importin which normally mediates the translocation to the nucleus of SR proteins. Several mutations of TNPO3, all resulting in a mutated protein that is 15-aminoacids longer in its C-terminal domain, have been described as causative of LGMDD2. However, the pathogenetic mechanism remains unknown. This project aims at investigating the pathogenesis of LGMDD2 utilizing an in vivo approach on the creation of a Zebrafish model of the disease. We focused on the role of TNPO3 on muscle development to identify any potential molecular pathways linked to the disorder. Microinjection of mRNAs, encoding the wild type or mutated form of human TNPO3 into Zebrafish embryos, was performed to follow their effects on the myogenic processes during development. The analysis revealed changes in the gene expression profiles of Myogenic Regulatory Factors and muscle-specific proteins and at phenotypical level by an aberrant organization of muscle fibers, as demonstrated by immunofluorescence and transmission electron microscopy studies. Functional tests showed that the mutants are less active in the open field test and have a less intense response to light turn on/off. These results suggest that our approach could be effective in establishing a Zebrafish model of LGMDD2 and hypothesizing of the role of TNPO3 in muscle development and differentiation as a possible pathogenetic mechanism of LGMDD2.