Abetalipoproteinemia

Etiology

• Deficiency of apolipoproteins (ApoB-48, ApoB-100)

• Due to a mutation in the microsomal triglyceride transfer protein (MTTP) gene

Pathophysiology

• Autosomal recessive disease

• Deficiency of chylomicrons, VLDL, and LDL (hypolipoproteinemia)

Clinical features

• Early

  • Steatorrhea

  • Failure to thrive

  • Fat malabsorption → fat-soluble vitamin deficiency

  • Acanthocytosis

• Late

  • Developmental delay

  • Retinitis pigmentosa

  • Myopathy

  • Progressive ataxia

Diagnostics

• Extremely low levels of plasma cholesterol (< 50 mg/dL)

• Acanthocytes in the blood

• Other tests performed include complete blood count with differential, stool studies, and fasting lipid profile.

• Confirmatory test: genetic testing to detect mutations in the MTTP gene

• Intestinal biopsy: Histology may reveal lipid-laden enterocytes.

Treatment

• Vitamin E supplementation (high doses)

• Reduced long-chain fatty acids intake