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Sensory Disorders: Large Fiber & Ataxic

Toxic
  Vitamin B6
  cis-platinum
  Semi-synthetic penicillins
  Taxol

Deficiency/ Malabsorption
  Vitamin B12
  Vitamin E

Immune
  Antibody
    GALOP
    GD1b antibody
    MAG
  Miller Fisher Syndrome
  Sensory ganglionopathy
    Hu (Paraneoplastic)
    Sjögren's
    Idiopathic

Infection
 Syphilis - Tabes dorsalis
Hereditary
  Recessive 2
    a-β-lipoproteinemia (Bassen-Kornzweig): MTP
    AOA2: SETX
    Ataxia Telangectasia: ATM
    AVED: TTPA
    CANVAS: RFC1
    DAIPT (Scoliosis): PIEZO2
    Friedreich Ataxia: FXN
    Mitochondrial
      POLG
      IOSCA: TWNK
      MC4DN11: COX20
    PCARP: FLVCR1
  Dominant
    Sensory ataxic neuropathy: PLD3
    Sensory ataxic neuropathy 2: 16q22
      SCA 4
    Sensory ataxia (SNAX1): RNF170; 8p11
    Posterior column ataxia (Biemond)
    Sensory neuropathy + Scoliosis (Robinson)

Also see
  Hereditary
    Ataxic neuropathy + Thermoanalgesia
    Sensory & Autonomic Neuropathies
    Mitochondrial: Sporadic
  More pathology
  Large and Small Axon loss
    Neuropathies
    Ganglionopathies

Peripheral Nerve
Loss of large myelinated axons

Posterior column ataxia (Biemond)

  Autosomal Dominant or Single generation

Sensory neuropathy with Scoliosis (Robinson)

  Autosomal Dominant

SCA46: Ataxia, Sensory Neuropathy + Cerebellar 1

  Phospholipase D family, member 3 (PLD3) ; Chromosome 19q13.2; Dominant
  • Epidemiology: 1 Dutch family; 5 patients
  • Genetics
    • Mutation: Missense; Leu308Pro
  • PLD3 protein
    • Catalyze hydrolysis of membrane phospholipids
    • Expression: High in cerebellum
    • Cell localization: Endoplasmic reticulum
  • Clinical
    • Onset age: 35 to 70 years
    • Sensory
      • Large fiber loss
        • Vibration: Reduced or Absent
        • Proprioception: Reduced
        • Distal > Proximal
        • Legs > Arms
      • Ataxia: Gait
      • Small fiber loss: Pain sensation mildly reduced
    • Strength: Normal
    • Reflexes: Reduced or absent in legs
    • Cerebellar
      • Eyes: Square wave jerks; Nystagmus; Saccades slow
      • Dysarthria
    • Course: Slow progression
  • Laboratory
    • Nerve conduction
      • SNAP amplitudes: Reduced or Absent
      • Conduction Velocity: Normal
    • Pathology
      • Myelinated axons: Reduced to 10% of normal
      • No regenerating clusters or onion bulbs
    • Sensory evoked potentials: Often unobtainable or reduced amplitude
    • Brain MRI: Normal or Cereberllar atrophy, mild

Sensory Ataxic Neuropathy 2

  Chromosome 16q22.1; Dominant

Toluidine blue stain

Loss of large myelinated axons with relative preservation of small myelinated axons

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References
1. Brain 1995;118:1557-1563
2. Nat Rev Neurol 2022 Mar 24

3/28/2022