What’s causing this teenager’s vision loss?

March 28, 2018

Figure 1 Quiz of the Week

A 14-year-old boy is brought to the pediatrician by his mother over concerns of difficulty walking and worsening clumsiness. He reports a gradual loss of night vision, and a long history of chronic diarrhea which is pale and foul-smelling. Examination reveals an ataxic gait, and loss of deep tendon reflexes. Bilateral retinitis pigmentosa is noted on fundoscopy and a peripheral blood smear reveals the findings seen here.

Which additional laboratory finding is most likely?

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Image credit: @bkehmsen.


Answer: Low total cholesterol level

This patient’s presentation and clinical findings are suggestive of abetalipoproteinemia, a form of neuroacanthocytosis. The condition, also known as Bassen-Kornzweig disease, is an autosomal recessive disorder characterized by neurologic impairment and the presence of acanthocytes (spiculated red blood cells) on a peripheral blood smear. Other notable laboratory findings include a low total cholesterol level, with an absence of beta-lipoproteins on electrophoresis. The resultant inability to absorb and transport vitamin E causes the neurologic manifestations associated with the disease.

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