Fig. 1

Phenotypic, myopathological, and electron microscopical findings in our patient with an overview of the UNC45B variant identified in this study. a Front and side view of our patient, showing hyperlordosis and obesity. b Gower’s sign in our patient. c Increased fiber size caliber spectrum with internalized nuclei predominantly in hypertrophic muscle fibers (arrows) and atrophic muscle fibers (arrowheads). H&E staining, original magnification × 400; scale bar 20 μm. d Disorganization of myofibrillary architecture evidenced by pale centers of muscle fibers presenting as core-like structures. Enzyme histochemistry with NADH; original magnification × 400; scale bar 20 μm. e Focal myofibrillary disintegration (arrows) and occasional non-subsarcolemmal muscle fiber nuclei. Semithin section, toluidine blue staining; scale bar 20 μm. f Subsarcolemmal core-like structure and Z-band streaming in electron microscopy (EM). g Pedigree and chromatograms of the index patient, healthy sisters, and healthy mother. The healthy father’s blood sample was unavailable for dideoxy sequencing. h UNC45B multiple sequence alignment made with Jalview shows high evolutionary conservation at amino acid residue p.Arg754 (NP_775259.1 Homo sapiens, the mutated sequence from our patient c.2261G > A p.Arg754Gln, XP_001174363.2 P. troglodytes, XP_0011113905.2 m. mulatta, XP_005624856.1 C. lupus, XP_002695676.1 B. taurus, NP_848795.3 m. musculus, NP_001100498.1 R. norvegicus, XP_004946569.1 g. gallus, NP_705959.1 D. rerio, NP_001172057.1 x. tropicalis, NP_524796.1 D. melanogaster, XP_310258.5 A. gambiae, and NP_497205.1 C. elegans). i Variant in the UNC45B gene (NM_173167.3, 20 exons) identified in our patients and concomitant position in the j. UNC45B protein structure (Q8IWX7) based on 931-aa isoform (ENST00000268876.9, NP_775259.1); pictogram with protein domains: Tetratricopeptide repeats (TPR, red) and Armadillo/beta-catenin-like repeats (ARM, green), N-terminal region of protein in blue, central region (131–506) in white, UCS region (Unc45−/Cro1p−/She4p-related protein) in red (507–931). Gene and protein sequences are drawn with the IBS Biocuckoo web server [14]