Myopathy with DNAJB6 mutations (LGMD 1 E)

Muscle fibers: Varied size

H&E stain Large and small rounded muscle fibers. Fibers with vacuoles. Some internal nuclei, Gomori trichrome stain Large and small rounded muscle fibers. Some fibers have vacuoles with red staind contents. VvG stain

Muscle fiber types: Type 1 small; Type 2 predominant

ATPase pH 9.4 Varied fiber size: Type 1 & some Type 2 fibers are small. The largest fibers are Type 2.

DNAJB6: Other

NADH stain Internal architecture is unremarkable. Small type 1 muscle fibers are dark stained.

VvG stain Intermedate-sized perimysial vessels and intramuscular nerves are normal.

Esterase stain Neuromuscular junctions are multi-segmented.

DNAJB6 myopathy: Vacuoles in large & small muscle fibers
H&E stain	H&E stain

Gomori trichrome stain

Vacuoles with reddish contents

VvG stain

Congo red stain

Vacuoles associated with basophilic granular debris

DNAJB6 myopathy: Aggregate proteins in muscle fibers SMI-31 Small & Large SMI-31+ aggregates in muscle fiber (Right)
TDP-43 TDP-43+ aggregates in muscle fiber cytoplasm	TDP-43 Desmin stains cytoplasm in some small muscle fiber but no aggregates.

Caveolin-3 Caveolin-3 is reduced on sarcolemma.

Caveolin-3 Control muscle: Normal caveolin-3 staining.