(A) Left quadriceps muscle biopsy performed at age 10 months (i-iii) demonstrating a dystrophic process with variation in fiber size (black arrow), increased connective tissue (blue arrow) and rare internalized nuclei (white arrow) on hematoxylin and eosin (H&E) staining (i) and Gömöritrichrome staining (ii) and type 1 fiber atrophy on nicotinamide adenine dinucleotide (NADH) staining (iii). Muscle biopsy in an unaffected (control) individual (iv-vi). Scale bar: 100μm. 