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Collagen VI myopathies (Ullrich congenital muscular dystrophy (UCMD), Bethlem myopathy (BM), and myosclerosis myopathy) share a common pathogenesis, that is, mitochondrial dysfunction due to deregulation of the permeability transition pore (PTP). This effect was first identified in the Col6a1−/− mouse model and then in muscle cell cultures from UCMD and BM patients; the normalizing effect of cyclosporin A (CsA) confirmed the pathogenic role of PTP opening. In order to determine whether mitochondrial performance can be used as a criterion for inclusion in clinical trials and as an outcome measure of the patient response to therapy, it is mandatory to establish whether mitochondrial dysfunction is conserved in primary cell cultures from UCMD and BM patients. In this study we report evidence that mitochondrial dysfunction and the consequent increase of apoptotic rate can be detected not only, as previously reported, in muscle, but also in fibroblast cell cultures established from muscle biopsies of collagen VI-related myopathic patients. However, the mitochondrial phenotype is no longer maintained after nine passages in culture. These data demonstrate that the dire consequences of mitochondrial dysfunction are not limited to myogenic cells, and that this parameter can be used as a suitable diagnostic criterion, provided that the cell culture conditions are carefully established. J. Cell. Physiol. 227: 2927–2935, 2012. © 2011 Wiley Periodicals, Inc.

Neuromuscular diseases (NMDs) represent a wide cluster of heterogeneous rare disorders that affect peripheral nervous system, causing defects in the development or functioning of muscles and damages in neuromuscular junctions or in associated nerves. The NMDs are characterized by high clinical and genetically heterogeneity, occurrence of mutations in largest genes, lack of genetic diagnosis for about 40% of the patients. To identify disease causing genes involved in NMDs, we performed, the whole exome sequencing (WES) in two “families of four” affected by congenital muscular dystrophy and congenital myopathy respectively, and the Gene Panel test in third family with motor neuropathy. We identified few candidates genes that are been technically validated by Sanger sequencing in the two family analysed by WES.. In the family with a congenital muscular dystrophy we found a known pathogenic in-frame deletion of the ISPD gene (Isoprenoid Synthase Domain-Containing Protein), previously sequenced with negative result. In the second family with congenital myopathy we identified a mutation in RYR1 gene (Ryanodine Receptor 1), previously screened only for mutations in the hot spot regions. Finally in the third family with motor neuropathy we identified a variation in ATP7A gene (ATPase, Cu++transporting, alpha polypeptide) that define a novel phenotype not previously described and expanding the clinical spectrum associated to ATP7A mutations. In conclusion this study provides evidence that next-generation sequencing can have high success rates in a clinical setting. WES has identified known gene mutations and corrected non exhaustive diagnostic procedures, also showing to be a powerful tool for hereditary motor neuropathies diagnosis and new phenotype discovery.