Abetalipoproteinemia

Etiology
  • Abetalipoproteinemia is a hereditary deficiency of a protein which transfers lipids to nascent Apolipoprotein B-containing chylomicrons and VLDLs normally synthesized by the small intestine and liver.
Pathogenesis and Morphology
  • Failure to properly export lipids from the small intestine mucosa causes build up of lipids in enterocytes which appear filled with lipid vacuoles. Lipid buildup in enterocytes reduces their capacity to absorb lipids from ingested food and thus yields a lipid malabsorption syndrome. Long-term inability to absorb lipids leads to a deficiency of critical fatty acids required for plasma membrane maintenance most obviously manifested in erythrocytes which appear as acanthocytes.
Clinical Consequences
  • Abetalipoproteinemia presents in infancy as failure to thrive and steatorrhea.
Laboratory Features
  • Nearly undetectable levels of plasma VLDL and LDL.