fig4

Figure 4. Comparative XLMTM histopathologic lesions in a MTM1 knockout mouse (43 days, mid-stage), dog (18 weeks, end-stage), and boy (2 months, terminal-stage). Increased numbers of central nuclei (inset in human sample) and fiber size variation due to numerous hypotrophic and atrophic (human) fibers are seen on H&E and PAS stains. Organelle (NADH) and glycogen (PAS) mislocalization is evident as either peripheral halos (human) or dark peripheral staining (dog and mouse). “Necklace fibers” (arrows) are seen in canine, some human patient biopsies (NADH inset), and rare mouse fibers. Scale bar = 40 µm. From Lawlor et al., 2016^[28]. Republished under Creative Commons Attribution License (CC-BY 3.0). XLMTM: X-linked myotubular myopathy.