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Mitochondrial disease: Cytochrome oxidase deficiency, Children

1 month old child 6 month old child   Ultrastructure

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COX Deficiency: 6 month old child

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H&E stain

Muscle fibers with "Cracks" & Small, round holes

Gomori trichrime stain

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"Checkerboard" pattern of fiber types
  "Cracks" & Small round holes are more prominent in type I (pale) fibers

ATPase, pH 9.4

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Type 2C (Immature; Intermediate-staining), muscle fibers: Increased numbers (> 5%)

ATPase, pH 4.3

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Sudan black

Large lipid droplets in many fibers

Toluidine blue

Toluidine blue

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Cytochrome oxidase
  Reduced staining in all fibers

COX stain

COX stain

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Succinate dehydrogenase (SDH)
  Increased staining in many fibers

SDH stain

SDH stain

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Mitochondrial Infantile Encephalopathy, Ultrastructure

From: R Schmidt

Mitochondria
  Proliferation
  Shapes & structure: Irregular
  Sizes: Often large
Lipid droplets
  Scattered in muscle fibers

From: R Schmidt

From: R Schmidt

Mitochondria
  Proliferation
  Shapes & structure: Irregular
  Sizes: Often large
Lipid droplets
  Scattered in muscle fibers

From: R Schmidt

From: R Schmidt

Mitochondria
  Shapes & Structure: Irregular
  Sizes: Often large

From: R Schmidt

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COX Deficiency: 1 month old child

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COX stain

Cytochrome Oxidase (COX) is diffusely reduced in muscle fibers

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COX stain

Cytochrome Oxidase (COX) is diffusely reduced in muscle fibers, but preserved in
  Perimysial vessels (Arrow)
  Intrafusil spindle fibers

COX stain

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SDH stain

Succinate Dehydrogenase (SDH) is mildly increased in some muscle fibers (Arrow)

SDH stain

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Type 2C muscle fibers (Intermediate staining): Increased numbers

ATPase pH 4.3 stain

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Lipid Droplets: Increased size

Sudan black stain

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Glycogen (PAS staining) is increased in muscle fibers

PAS stain

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7/8/2025