PMC6431376_01
Muscle biopsy: (a) hematoxylin eosin; (b) staining for cytochrome oxidase; (c) succinate dehydrogenase (SDH) staining; (d) Gomori trichrome stain.
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fig1
MEP 5,17 kPA, n.v. >10,2). Muscle biopsy revealed ragged red and ragged blue fibers and COX negative fibers (Figure 1).
Long-PCR analysis of mitochondrial DNA in muscle tissue: on the left, the test performed on our patient, which shows multiple deletions of mtDNA, and, on the right, a normal control.
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fig2
Long-PCR analysis, in muscle tissue, showed mtDNA multiple deletions (Figure 2), and next-generation sequencing (NGS) analysis detected two DGOUK compound heterozygous mutations: the known pathogenetic variant c.462T>A (p.Asn154Lys) and a new variant of the donor splice site of intron 5 c.707+2T>G, predicted to alter the splicing on Human Splicing Finder (http://www.umd.be/HSF3/HSF.shtml) and thus considered pathogenetic.