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CMT 1A

Muscle Nerve   Schwann cells

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Nerve

Toluidine blue

Onion Bulbs
  Some contain myelinated axons; Others are empty ("Obsolete")
  Myelin sheaths: Thick; Normal or Thin
  Contain abundant non-myelinating Schwann cells

Toluidine blue

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Axons
  Reduced numbers: Large & Small
  Some onion bulbs have no axons
  Some small axons are present in layers within & around onion bulbs

SMI31: Neurofilament

SMI31: Neurofilament

SMI31: Neurofilament

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Schwann cells in Onion bulbs

Contain: NCAM & P0 protein

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NCAM

Non-myelinating Schwann cells in onion bulbs: In layers
Myelin around central axons: Abnormal; Stains for NCAM

NCAM

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Schwann cells in Onion bulbs also contain P0 protein

Neurofilament (Green) & P0 (Red) stains

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CMT 1A: Muscle

Fiber size
  Large fibers: Hypertrophied
  Small fibers: Very small; Grouped; Some pyknotic nuclear clumps

H&E

H&E

Grouped atrophy
Perimysium: Replaced by fat

Congo red

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Small muscle fibers: Dark on NADH stain

NADH

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Fiber types
  Large fibers: Type grouping
  Small fibers: Grouped; Type 2

ATPase pH 4.3

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Chronic changes: Perimysium is replaced by fat

Sudan black

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Return to Normal nerve biosies
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Return to CMT 1A
Return to Neuromuscular Home Page
Return to Nerve biopsy
Return to Demyelinating neuropathies
Return to Chronic demyelination

1/18/2017