case_images: PMC10831852_01
case_images: (A) Graphic of the typical LGMDR8 phenotype. The five sections summarize the most frequent clinical and instrumental features, drawn from the analysis of the 53 LGMDR8 TRIM32-mutated patients (including our case) reported in the literature; (B) timeline highlighting our patient's clinical history and diagnostic work-up. Figures (A, B) were created with BioRender.com.
case_images: fneur-14-1281953-g0001.jpg
case_images: PMC10831852_01_fneur-14-1281953-g0001.jpg
case_images: F1
case_images: Electromyography (EMG) and electroneurography (ENG), performed at the early stage of the disease, showed a myopathic pattern of the quadriceps femoris, supporting the diagnosis of a pelvic girdle myopathy (clinical timeline is displayed in Figure 1B). This revealed diffuse morphological changes in several muscles of the upper and lower limbs (Supplementary Figure 1), with a severe fibroadipose degeneration involving the shoulder and pelvic girdles.
case_images: Histological and immunohistochemical findings in muscle biopsy. (A, B) Hematoxylin and eosin (A) and modified Gomori trichrome (B) stains showing markedly increased fiber size variability, central nuclei, severe fibro-adipose replacement (asterisks), splitting fibers (arrowheads), internal vacuoles (arrow). (C) ATPase pH 9.4 stain showing predominant type 2 (darker) fibers atrophy. (D) NADH-TR stain showing preserved oxidative enzymes activity in most of the observed fibers, with darker stain of the atrophic fibers. (E, F) Immunofluorescence assay showing increased intracellular accumulation of myotilin (E) and desmin (F) proteins compared to control muscles (small frames). (G) Immmunofluorescence assay showing increased cytoplasmic p62 signal compared to control muscle (small frame). Scale bars: 100 mum (A-D) 25 mum (E-G).
case_images: fneur-14-1281953-g0002.jpg
case_images: PMC10831852_01_fneur-14-1281953-g0002.jpg
case_images: F2
case_images: Furthermore, there was evidence of numerous splitting fibers, subsarcolemmal and intracytoplasmic vacuoles containing finely granular material, without the presence of sarcotubular aggregates (Figures 2A-D). Immunohistochemistry showed desmin and myotilin accumulations within muscle fibers, as well as increased p62 detection compared to control muscles (Figures 2E-G).
case_images: Schematic representation of the TRIM32 gene (A) and TRIM32 protein (B), displaying the structural domains and intermediate regions with the LGMDR8-associated biallelic variants (that are listed with the same color coding in Table 1). The two variants (c.1181G > A, p.Arg394His; c.1781G > A, p.Ser594Asn) carried by our patient are outlined in red (B) and also shown in the chromatograms (C). Figures (A, B) were created with BioRender.com.
case_images: fneur-14-1281953-g0003.jpg
case_images: PMC10831852_01_fneur-14-1281953-g0003.jpg
case_images: F3
case_images: TRIM32 variants (Figures 3B, C): c.1181G > A/p.(Arg394His), and c.1781G > A/p.(Ser594Asp). These were already described by Saccone et al. and Panicucci et al., and classified as class 4 (likely pathogenic) and class 3 (of uncertain significance) variants, respectively, according to the ACMG (American College of Medical Genetics and Genomics) criteria (Figure 3). Proband's parents or relatives were not available for segregation testing.