ATP Synthase Deficiency due to TMEM70 Mutation Leads to Ultrastructural Mitochondrial Degeneration and Is Amenable to Treatment

Figure 5

Electron microscopy reveals altered mitochondria morphology. Ultrastructural findings in muscle biopsies, child I (a, b), child IV (c, d), and child II (e–h), magnification as indicated by the scale bar. We detected abnormal mitochondria with concentric cristae (a, cc) as well as subsarcolemmal (sl) accumulation of swollen mitochondria (m) with crystalline inclusions (ci) in child I (b). In child IV, sample quality was not optimal; degenerated mitochondria (m) were detected (c, d). In child II (e–h), we detected accumulations of swollen mitochondria with abnormal cristae structure and separated inner (sim) and outer membrane with vacuoles (v), (g) possibly by intramitochondrial lipid accumulation with cristae aggregation. Additionally, we saw protruding membranes filled with amorphous and electron dense material, most possibly mitochondria (f, g). Extracellular abnormal membranous structures (m, dense globular inclusion) were detached from the main myofibre (h).

(a)  

(b)

(c)

(d)

(e)

(f)

(g)

(h)