What is the role of genetics in the pathophysiology of abetalipoproteinemia (ABL)?

Updated: Mar 06, 2018
  • Author: Vibhuti N Singh, MD, MPH, FACC, FSCAI; Chief Editor: George T Griffing, MD  more...
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Answer

Formation and exocytosis of CMs at the basolateral membrane of intestinal epithelial cells is necessary for the delivery of lipids to the systemic circulation. One of the proteins required for the assembly and secretion of CMs is MTP. The gene for this protein (MTP) is mutated in patients with ABL. [10, 11]

Several mutations in the MTP gene have been described. In most patients with ABL, the mutation involves a gene encoding the 97-kd subunit of MTP. Consequently, children with ABL develop fat malabsorption and, in particular, suffer the results of vitamin E deficiency (ie, retinopathy, spinocerebellar degeneration). [12] Biochemical test results show low plasma levels of apoB, triglycerides, and cholesterol. Membrane lipid abnormalities also affect the erythrocytes, causing acanthocytosis (burr cells). Long-chain fatty acids are very poorly absorbed, and the intestinal epithelial cells become engorged with lipid droplets. Such children respond to a low-fat diet rich in medium-chain fatty acids, as well as to supplementation with high-dose, fat-soluble vitamins, especially vitamin E. [13]


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