Question

A 6-year-old child presents with progressive ataxia, loss of deep tendon reflexes, and peripheral neuropathy. Vitamin B12 deficiency has been excluded, and MRI spine is normal. Which vitamin deficiency is most likely responsible?

• A. Vitamin A
• B. Vitamin B1
• C. Vitamin E
• D. Vitamin D

Hint:

Neuro-Vitamin Deficiencies:
$\bullet$ Vitamin E deficiency $\rightarrow$ Spinocerebellar ataxia + Areflexia + Loss of proprioception/vibration (mimics Friedreich ataxia).
$\bullet$ Vitamin B1 (Thiamine) $\rightarrow$ Wernicke encephalopathy Beriberi.
$\bullet$ Vitamin B12 $\rightarrow$ Subacute combined degeneration (posterior + lateral columns).

Answer 1

The Correct Option is C

Concept:
Vitamin E ($\alpha$-tocopherol) is a critical lipid-soluble antioxidant that protects long, heavily myelinated axons and neuronal membranes from reactive oxygen species-induced peroxidative damage.
Chronic Vitamin E deficiency leads to a severe, progressive spinocerebellar neurodegenerative syndrome that clinically mirrors Friedreich ataxia.
Explanation:
• Vitamin E deficiency in children occurs secondary to severe fat malabsorption (e.g., cystic fibrosis, biliary atresia, cholestatic syndromes, abetalipoproteinemia) or an autosomal recessive genetic defect in the $\alpha$-tocopherol transfer protein (Ataxia with Vitamin E Deficiency, AVED, due to TTPA gene mutations).

• The pathological hallmarks are degeneration of the large-caliber myelinated sensory fibers in the posterior columns (gracile and cuneate fasciculi), spinocerebellar tracts, and peripheral sensory nerves.

• Clinically, affected children develop progressive sensory and cerebellar ataxia, dysmetria, intentional tremor, loss of deep tendon reflexes (areflexia), and impaired vibration and proprioception sensations with a positive Romberg sign.

• Advanced or prolonged deficiency causes secondary axonal peripheral sensorimotor neuropathy, ophthalmoplegia, and pigmented retinopathy.

• While subacute combined degeneration of the cord from Vitamin B12 deficiency produces similar posterior/lateral column signs, normal B12 levels point directly to Vitamin E deficiency.
Final Answer:
Chronic Vitamin E deficiency is responsible for the Friedreich ataxia-like syndrome of progressive ataxia, areflexia, and peripheral neuropathy.