Figure 5.

Subsarcolemmal accumulation of mitochondria and amorphous electron-dense material in soleus from Hom T4826I-RYR1 males. A) Sectioned profiles of mitochondria in WT fibers are evenly distributed on either side of the Z line (small arrows and inset) and occasionally as single longitudinally oriented elements (larger arrows). Large island of subsarcolemmal mitochondria is also seen (star). Arrowheads indicate the plasmalemma. B) In mutant fibers, peripheral accumulations of mitochondria are larger and also contain abundant amorphous electron-dense material and are in proximity of fiber regions that lack intermyofibrillar mitochondria (dashed box). C) Unusually large peripheral regions devoid of myofibrils (stars) in this light microscope image correspond to accumulations of mitochondria.