Titin

Titin Myopathies

Dominant
Recessive

Titin Myopathy: Recessive, Fiber type size disproportion

1 year old female

H&E stain
Muscle fibers
Size: Varied
Internal nuclei

H&E stain

Muscle fibers
Some are very small
A few have central nuclei

H&E stain

Fiber size: Varied

Gomori trichrome stain

VvG stain

Fiber size
Varied
Some regions have more very small fibers than others

VvG stain

Vessels: Normal structure

VvG stain

NADH stain

Internal architecture: Smudged, & diffusely stained, in some small muscle fibers

NADH stain

ATPase pH 9.4 stain
Fiber types
Type II: Are the largest
Type I: Many very small
Type IIC fibers: Few; Scattered

ATPase pH 4.3 stain

Mitochondria: Normal

SDH stain

Muscle fiber cytoplasm: Some muscle fibers have diffuse staining or small aggregates

AMPDA stain

Desmin: Small muscle fibers are darker stained

Desmin stain

Titin Myopathy: Dominant, Cytoplasmic Aggregates

12 year old female: Titin mutation G25588R

Chronic myopathy
Muscle fiber size: Varied
Perimysial connective tissue: Replaced by fat

H& E stain

H& E stain

Muscle fibers
Aggregates
Nuclei: Large & Irregular
Size: Varied

H& E stain

Congo red stain

Myonuclei: Irregular Shapes; Large

Congo red stain

Cytoplasmic Aggregate

Gomori trichrome stain

VvG stain

Cytoplasmic Aggregates
Shapes: Varied

VvG stain

Cytoplasmic Aggregates: Stain for desmin

Desmin stain

Cytoplasmic Aggregates: Smudged internal architecture

NADH stain

Internal architecture, Other fibers: Irregular

NADH stain

AMPDA stain

Cytoplasmic aggregates

AMPDA stain

Cytoplasmic granules: Acid phosphatase stained

Acid phosphatase stain

Type I muscle fiber prodominance

ATPase pH 4.3 stain

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3/21/2016