The lipoproteins and lipid transport in abetalipoproteinemia.

The disease abetalipoproteinemia results in intriguing disturbances of lipid transport (2, 3). Included among its manifestations are an inability to form chylomicrons (4) and the lowest concentrations of plasma lipids detected in any human disorder. In this familial syndrome it is possible that the elaboration of beta lipoprotein, or more strictly its beta or B apoprotein, is primarily affected by mutation. This is one of two proteins known to be constituents of human plasma lipoproteins. Abetalipoproteinemia offers unique opportunities for probing the functions of and specific requirements for the B apoprotein and for observing compensating mechanisms aroused by its deficiency. Some explorations into these aspects of the disease have already been made (2-6). This paper adds the following studies: 1) more intensive immunochemical analyses of the plasma lipoproteins than have heretofore been made to determine whether any detectable quantities of beta lipoprotein are present, 2) identification of the protein present in the "low density lipoproteins" frequently reported in this disease, 3) examination of the alpha lipoproteins and their A apoprotein in abetalipoproteinemia, and 4) experimental determination of the effect of B apoprotein deficiency on endogenous glyceride transport.