High density lipoprotein (HDL) and whole serum from a patient with abetalipoproteinemia (neither of which contains a component that binds to the LDL receptor) did not produce a significant increase in the content of either cholesterol or cholesteryl esters in normal cells.
The significance of mucosal apolipoprotein B content in abetalipoproteinemia is discussed in terms of factors controlling apolipoprotein B synthesis in normal mucosa and in abetalipoproteinemia.
Although some subjects showed acanthocytosis total cholesterol (0.63 +/- 0.05 mol x 10(-6)/mg membrane protein) and sphingomyelin/lecithin ratio (0.905 +/- 0.042) of RBC membranes were normal while plasma from the subject with schistocytosis had a significantly decreased sphingomyelin/lecithin ratio in plasma (17.2 +/- 2.4 vs. 29.1 +/- 3.3) suggesting that sphingomyelin and lecithin are not freely exchangeable between plasma and the outer surface of RBC membranes.
Amyotrophic choreo-acanthocytosis is a rare disease of adult onset characterized by dyskinesias, neurogenic muscular atrophy, erythrocytary acanthocytosis with normal serum lipoproteins and elevated levels of serum CPK.
Four complementary DNA probes for apoB-100 covering the 5', middle, and 3' regions of the apoB-100 mRNA were utilized and Southern blot analysis indicated that the apoB-100 gene is present in abetalipoproteinemia without major insertions or deletions.