Figure 4.

Pedigree, MRI and immunohistochemical staining for the COL6A2 family

(A) Pedigree of the COL6A2 family. VIII:1 and VIII:2 are homozygous for the COL6A2 NM_001849.3:c.2423-22_2423-21insAGCCCGGCCCGGCCC variant (+/+) and their parents (VII:1 and VII:2) were both heterozygous (+/−). VII:1 and VII:2 are distantly consanguineous.

(B and C) Muscle MRIs for both VIII:1 and VIII:2 show peripheral involvement of thigh and calf muscles, in particular the vastus lateralis (top, arrows) and gastrocnemii (bottom, arrows), typical of those described in collagen-VI-related myopathies.³² (C) Immunohistochemical staining shows reduced, but present, collagen staining in a skeletal muscle biopsy from VIII:2, and present staining in VII:2. Sequential 8 μm thick cryosections of snap frozen skeletal muscle were stained with anti-spectrin, and anti-collagen VI (red) co-stained with anti-perlecan (green) antibodies. In healthy control muscle (C1, 28 years, vastus lateralis), collagen VI stains the muscle sarcolemma as well as the endomysium, whereas perlecan only stains the sarcolemma. In VIII:2 (12 years, quadriceps), collagen VI staining of the sarcolemma is reduced and endomysium staining is normal/increased. In VII:2 (28 years, unknown muscle type), collagen VI staining is within normal limits. Scale bar 100 μm (white line).