SELENON and myopathy: It is also possible that the observed reduction in mitochondrial Ca2+ uptake in isolated fibers of the FDB from CrT−/y mice could at least in part be due to the reduction in the number of CRU-mitochondrial pairs/100 μm2 (Fig. 4D) as previously reported in ageing [47] and in SEPN1-related myopathy patients [48, 49].