Lipoprotein congenital deficiency

A further understanding of the nature of the chylomicron protein may derive from studies of chylomicron formation in patients with congenital deficiency of the plasma high-density (Fredrickson, 1961) or low-density lipoproteins (Salt et al., 1960a,b) (see Section VI, F for details). 

The presence of LDL in chylomicrons has been detected by immunochemical means (Middleton, 1956 Scanu and Page, 1959). A functional role of this lipoprotein in chylomicron formation has been suggested by the observation that patients with congenital deficiency of LDL, a rare disorder (see Section VI, F, 2, b) do not form chylomicrons. Direct experimental proof is not presently available to support a cause-eflEect relationship between deficiency of LDL and the abnormal absorptive process. 

Dietary deficiency of vitamin E in human beings is unknown, although patients with severe fat malabsorption, cystic fibrosis, some forms of chronic liver disease or (very rare) congenital lack of plasma 3-lipoprotein suffer deficiency because they are unable to absorb the vitamin or transport it around the body. They suffer from severe damage to nerve and muscle membranes. 

There are several types of hyperlipoproteinaemias (see separate entry). Congenital deficiencies of lipoproteins can also occur. 

While congenital HL deficiency is associated with increased levels of plasma total TG, the pattern of lipoprotein abnormalities is more variable and less clear-cut than that of LPL deficiency. It seems probable that other plasma and ELs can take over many of HL s functions. 

R. ScHEiG, G. R. Plotkin, and J. B. Caulfield Congenital j5-lipoprotein deficiency an hereditary disorder involving a defect in the absorption and transport of lipids. Medicine (Baltimore) 43, 347—361 (1964). 

Dobbins, W. O., 1966, An ultrastructural study of the intestinal mucosa in congenital j8-lipoprotein deficiency with particular emphasis upon the intestinal absorptive cell. 

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