New Clinical and Immunofluorescence Data of Collagen VI-Related Myopathy: A Single Center Cohort of 69 Patients

Figures

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  Figure 1. Bar chart showing frequencies for each grade of contracture (normal, mild, moderate, severe) and phenotype (BM, MM, INTM, UCMD) among the six joints tested (AF, EF, FF, KF, MO, NF) (A). The chi-square test of independence showed that the relationship between these variables was higly significant for all six different joint contractures examined (B).

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  Figure 2. Bi-directional limitation in the range of motion in COL6-RM patients. The normal range of motion of elbow is 0–150° (full extension–full flexion). In this 55-year-old MM patient, the elbow could be moved in extension up to 69° and in flexion up to 111°, for a range of motion of only 42 degrees compared to the normal 150° (A). The normal range of knee flexion/extension is 150. In this 67-year-old BM patient, in the supine position, due to the contracture of the hamstrings, the knee could be extended 100° and remained flexed 50° (B). In the same patient in the prone position, due to the quadriceps contracture, the knee could only be flexed 66° (knee extension 84°) (C). The combined knee extension/flexion movement was 166° (100 + 66) compared to the normal 300° (B,C).

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  Figure 3. Box plots of percentage of predicted knee extension (A), elbow flexion (B), and hand grip (C) muscle strength in BM, MM, INTM, and UCMD patients. Significance of group versus group comparison (D).

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  Figure 4. Box plots of percentage of predicted FVC (A) in BM, MM, INTM, and UCMD patients. Significance of group versus group comparison (B).

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  Figure 5. Kaplan–Meier curves depicting ventilation-free status by age and COL6-RM phenotype (A). Kaplan–Meier curves showing the probability of loss of ambulation by age and COL6-RM phenotype (B).

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  Figure 6. Immunofluorescence analysis of collagen VI (Col6, green) and the basement membrane component perlecan (red), and superimposed images (merge) on cross-sections of muscle biopsies of COL6-RM patients, showing the 4 main immunohistochemical patterns: N, normal expression and localization of collagen VI, as demonstrated by the overlap of collagen VI with the anti-perlecan staining in merge image; mR, partial deficiency in collagen VI in the basement membranes of muscle fibers (arrowheads), also evidenced by partial co-localization with anti-perlecan antibody; MR, diffuse loss of collagen VI labeling in the basement membrane of muscle fibers and accumulation of mutated protein in perivascular endomysial areas; A, absence of collagen VI. Scale bar, 100 µm.

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  Figure 7. Immunofluorescence analysis of collagen VI (Col6, green) and the basement membrane component perlecan (red), and superimposed images (merge) on cross-sections of muscle biopsies of a healthy control and Col6-RM patients, performed at the indicated age. The first muscle biopsy in the three patients showed a mild reduction in collagen VI in Pt 12 (arrowheads), a marked reduction in Pt 40, and only a trace in patient Pt 52 (arrow). Scale bar, 50 μm (A). The repeated biopsies from the same Col6-RM patients show a striking increase in collagen VI amount around muscle fibers, with respect to the first biopsy. The change in the collagen VI pattern is particularly evident when comparing the first biopsy (shown in (A)) with the second biopsy (shown in (B)) in Pt 40 and Pt 52. Scale bar, 50 µm.