Vitamin E

• Potent lipid-soluble antioxidant.
• Protects cell membranes (especially RBCs and neurons) from free radical damage/oxidation.
• Highest concentration found in membranes with high polyunsaturated fatty acid (PUFA) content.

Vitamin E deficiency

• Etiology/Causes of Deficiency
  • Rare; almost exclusively seen in states of fat malabsorption:
    • Cystic fibrosis (pancreatic insufficiency)
    • Celiac disease
    • Crohn disease
    • Biliary obstruction / Cholestatic liver disease
  • Abetalipoproteinemia: Autosomal recessive defect in MTP gene, leading to inability to synthesize apolipoprotein B. Results in malabsorption of fat and fat-soluble vitamins (A, D, E, K).
  • Premature infants (low stores).
• Clinical Features
  • Neurologic dysfunction (highly dependent on Vitamin E for membrane protection) is the most prominent feature.
  • Presents similarly to Friedreich Ataxia.
  • Spinocerebellar ataxia: Difficulty with balance and coordination.
  • Myopathy: Skeletal muscle weakness.
  • Polyneuropathy:
    • Loss of deep tendon reflexes (areflexia).
    • Loss of proprioception and vibratory sense (due to dorsal column degeneration).
  • Hemolytic anemia: RBC membrane fragility leads to premature destruction.
  • Retinitis pigmentosa.
• Diagnostics
  • Labs: ↓ serum tocopherol levels.
  • Peripheral smear: May show acanthocytes (“spur cells,” especially in abetalipoproteinemia) and signs of hemolysis.