A pronounced contraction-induced increase in basal [Ca2+]mit similar to that in enzymatically dissociated fibers has previously been observed in mechanically dissected muscle fibers from a mouse model of severe mitochondrial myopathy, the fast-twitch skeletal muscle fiber-specific mitochondrial transcription factor A knock-out (Tfam KO) mouse, and this increase was implied to have a central role in the disease progress.42 Here, TFAM is linked to Mitochondrial myopathy.