Neuromuscular

FKRP mutations

Congenital Muscular Dystrophy
Limb Girdle Muscular Dystrophy 2I

FKRP: Congenital Muscular Dystrophy (MDDGB5)



H & E stain

 

 
Myopathy: Mild active & chronic changes
  Necrosis & Regeneration: Scattered
  Fiber size: Varied
    Small fibers: Rounded
  Endomysial connective tissue: Normal or Slightly increased
  Internal nuclei: Some fibers

H & E stain

Gomori trichrome stain


Acid phosphatase stain
Necrotic muscle fibers: Phagocytosis

Esterase stain

Necrotic (pale) muscle fiber (arrow)
Type I fiber predominance


NADH stain
Regenerating, immature muscle fibers: Coarse internal architecture (Arrow)
NADH stain

Fiber types

ATPase pH 9.4
Type I fiber predominance

ATPase pH 4.3
Scattered 2C fibers

Neuromuscular Junctions: Normal

Esterase stain

Intramuscular nerves: Normal

VvG stain


α Dystroglycan
FKRP mutations:
  Absent α-Dystroglycan around muscle fibers

α Dystroglycan
Control muscle:
  Normal α-Dystroglycan around muscle fibers

Desmin stain
Desmin: Stains cytoplasm in small regenerating fibers


MHC Class I stain
MHC-I is abnormally present on clusters of muscle fibers

MHC Class I stain

FKRP: Limb-Girdle Muscular Dystrophy 2I (LGMD 2I; MDDGC5)


H&E stain
FKRP: Chronic & Ongoing Myopathy
  Fiber size: Varied; Hypertrophic & Small
  Nuclei: Some are Internal or Large
  Partially fused (or Split) fibers
  Necrosis & Regeneration: Scattered

H&E stain


H&E stain
FKRP: Ongoing Myopathy
  Necrosis & Regeneration: Scattered
  Immature muscle fibers
    Internal architecture: Coarse
    Nuclei: Large
    Size Intermediate or Small

H&E stain

Gomori trichrome stain
FKRP: Ongoing Myopathy
  Necrosis: Muscle fibers replaced by phagocytic cells
  Immature muscle fibers: Coarse internal architecture
    Internal architecture: Coarse
    Nuclei: Large
    Size Intermediate or Small

NADH stain

Alkaline phosphatase stain
FKRP: Ongoing Myopathy
  Immature muscle fibers: Cytoplasm stains for Alkaline phosphatase
  Necrotic fibers: Replaced by Acid phosphatase positive histiocytic cells

Acid phosphatase stain

FKRP: Ongoing Myopathy
  Immature muscle fibers: Intermediate color with ATPase pH 4.3 stain

ATPase pH 4.3 stain


H&E stain
FKRP: Chronic Myopathy
  Endomysial connective tissue: Increased between muscle fibers
  Partially fused (or Split) fibers
  Nuclei: Some are Internal
  Muscle fiber hypertrophy

VvG stain

Gomori trichrome stain

Partially fused (or Split) fiber

VvG stain


Congo Red stain
FKRP: Chronic Myopathy
  Amyloid: Deposited in vessel walls & around small msucle fibers

Congo Red stain

Congo Red stain

FKRP: Other changes

ATPase pH 9.4 stain
Type 2 fiber (Dark) predominance
FKRP: "Immune" changes

MHC Class I stain
MHC Class I: Upregulation by muscle fibers, Diffuse or Patchy

Acid phosphatase stain
FKRP: "Immune" changes
  Histiocytic cells (Acid phosphatase & CD4 positive) are present in Perimysial and Endomysial connective tissue

CD4 cell stain


α-Dystroglycan - Green; Caveolin-3 - Red
α-Dystroglycan (Green): Varied patterns
  Reduced or Absent on the surface of some muscle fibers (Above)
  Severely reduced on the surface of most fibers (Below)

α-Dystroglycan - Green; Caveolin-3 - Red


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11/1/2016