Abetalipoproteinemia is an autosomal recessive lipid disorder characterized by a lack of ApoB (ApoB-48 and ApoB-100).
The disorder is caused by a mutation in MTP (microsomal transfer protein), which impairs lipoprotein assembly, preventing fat from exiting the enterocyte. Lipoproteins like chylomicrons, VLDL, and LDL are absent from blood, while biopsy of the intestines reveals lipid-laden enterocytes.
Clinical manifestations include fat malabsorption and steatorrhea (foul-smelling fatty stools), failure to thrive in children, and deficiencies of fat-soluble vitamins (A, D, E, and K). Vitamin E (Tocopherol/Tocotrienol) deficiency contributes to spinocerebellar tract degeneration (causing ataxia or poor coordination) and acanthocytosis in patients. Other findings include retinitis pigmentosa (breakdown of the retina with retinal pigment deposits).
Treatment of abetalipoproteinemia includes a low-fat diet and Vitamin E supplementation.
Find this Abetalipoproteinemia mnemonic and more Lipid Disorders mnemonics among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.