Abstract
Clinical and biochemical characteristics of familial hypercholesterolemia (FH) heterozygotes possessing an abnormally high molecular weight low density lipoprotein receptor (HMWR) are reported. The disorder is transmitted as an autosomal dominant trait and is not distinguishable from classic heterozygous FH on clinical grounds. The average plasma low density lipoprotein (LDL) level is 360 mg/dl and tendon xanthomata and early coronary disease are present. LDL receptor activity is higher than expected. In skin fibroblast cultures two types of functional LDL receptors are present, one with a normal apparent native molecular weight of 140,000, and the other of 176,000. When immobilized on nitrocellulose paper both receptors bind LDL. Maximum 125I-LDL binding capacity of fibroblast monolayers is reduced only 20%, compared with 50% in typical heterozygous FH. Affinity for 125I-LDL is increased and a 38% reduction in the Michaelis constant for LDL is observed. When autologous 125I-LDL was injected intravenously, the fractional catabolic rate of LDL was 205% and the LDL apoprotein B production rate was 328% of that found in a typical heterozygous FH subject. Thus, both in vitro and in vivo testing indicated only a modest deficiency of LDL receptor activity. Kindred members possessing the HMWR had an associated abnormality of cholesterol biosynthesis. Cholesterol balance studies in three individuals with the HMWR trait demonstrated elevated cholesterol biosynthesis of two to three times the mean of normal subjects. These findings suggest that increased LDL production and increased cholesterol production may assume a significant role in the pathologic manifestations of heterozygous FH. Functional abnormalities in LDL receptor activity as measured in fibroblast culture may be relatively small.
Full text
PDF





Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Daniel T. O., Schneider W. J., Goldstein J. L., Brown M. S. Visualization of lipoprotein receptors by ligand blotting. J Biol Chem. 1983 Apr 10;258(7):4606–4611. [PubMed] [Google Scholar]
- Davignon J., Simmonds W. J., Ahrens E. H. Usefulness of chromic oxide as an internal standard for balance studies in formula-fed patients and for assessment of colonic function. J Clin Invest. 1968 Jan;47(1):127–138. doi: 10.1172/JCI105703. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GRUNDY S. M., AHRENS E. H., Jr, MIETTINEN T. A. QUANTITATIVE ISOLATION AND GAS--LIQUID CHROMATOGRAPHIC ANALYSIS OF TOTAL FECAL BILE ACIDS. J Lipid Res. 1965 Jul;6:397–410. [PubMed] [Google Scholar]
- Goldstein J. L., Brown M. S. The LDL receptor defect in familial hypercholesterolemia. Implications for pathogenesis and therapy. Med Clin North Am. 1982 Mar;66(2):335–362. doi: 10.1016/s0025-7125(16)31424-9. [DOI] [PubMed] [Google Scholar]
- Grundy S. M., Ahrens E. H., Jr, Salen G. Dietary beta-sitosterol as an internal standard to correct for cholesterol losses in sterol balance studies. J Lipid Res. 1968 May;9(3):374–387. [PubMed] [Google Scholar]
- Grundy S. M., Ahrens E. H., Jr The effects of unsaturated dietary fats on absorption, excretion, synthesis, and distribution of cholesterol in man. J Clin Invest. 1970 Jun;49(6):1135–1152. doi: 10.1172/JCI106329. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grundy S. M., Metzger A. L., Adler R. D. Mechanisms of lithogenic bile formation in American Indian women with cholesterol gallstones. J Clin Invest. 1972 Dec;51(12):3026–3043. doi: 10.1172/JCI107130. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Le N. A., Melish J. S., Roach B. C., Ginsberg H. N., Brown W. V. Direct measurement of apoprotein B specific activity in 125I-labeled lipoproteins. J Lipid Res. 1978 Jul;19(5):578–584. [PubMed] [Google Scholar]
- MATTHEWS C. M. The theory of tracer experiments with 131I-labelled plasma proteins. Phys Med Biol. 1957 Jul;2(1):36–53. doi: 10.1088/0031-9155/2/1/305. [DOI] [PubMed] [Google Scholar]
- MIETTINEN T. A., AHRENS E. H., Jr, GRUNDY S. M. QUANTITATIVE ISOLATION AND GAS--LIQUID CHROMATOGRAPHIC ANALYSIS OF TOTAL DIETARY AND FECAL NEUTRAL STEROIDS. J Lipid Res. 1965 Jul;6:411–424. [PubMed] [Google Scholar]
- Ostlund R. E., Jr, Hajek S. V., Levy R. A., Witztum J. L. Analysis of lipids and endothelial and smooth muscle cells of umbilical cord in familial homozygous hypercholesterolemia. Metabolism. 1981 Mar;30(3):285–289. doi: 10.1016/0026-0495(81)90153-0. [DOI] [PubMed] [Google Scholar]
- Ostlund R. E., Jr, Levy R. A., Witztum J. L., Schonfeld G. Familial hypercholesterolemia. Evidence for a newly recognized mutation determining increased fibroblast receptor affinity but decreased capacity for low density lipoprotein in two siblings. J Clin Invest. 1982 Oct;70(4):823–831. doi: 10.1172/JCI110678. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ostlund R. E., Jr, Pfleger B., Schonfeld G. Role of microtubules in low density lipoprotein processing by cultured cells. J Clin Invest. 1979 Jan;63(1):75–84. doi: 10.1172/JCI109281. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Patsch W., Ostlund R., Kuisk I., Levy R., Schonfeld G. Characterization of lipoprotein in a kindred with familial hypercholesterolemia. J Lipid Res. 1982 Nov;23(8):1196–1205. [PubMed] [Google Scholar]
- Patsch W., Witztum J. L., Ostlund R., Schonfeld G. Structure, immunology, and cell reactivity of low density lipoprotein from umbilical vein of a newborn type II homozygote. J Clin Invest. 1980 Jul;66(1):123–129. doi: 10.1172/JCI109825. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schwarz K. B., Witztum J., Schonfeld G., Grundy S. M., Connor W. E. Elevated cholesterol and bile acid synthesis in a young patient with homozygous familial hypercholesterolemia. J Clin Invest. 1979 Sep;64(3):756–760. doi: 10.1172/JCI109520. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Semenkovich C. F., Ostlund R. E., Jr, Levy R. A., Osa S. R. Low density lipoprotein receptor activity in homozygous familial hypercholesterolemia fibroblasts. J Biol Chem. 1982 Nov 10;257(21):12857–12865. [PubMed] [Google Scholar]
- Semenkovich C. F., Ostlund R. E., Jr, Yang J., Reaban M. E. Demonstration of functional low-density lipoprotein receptors by protein blotting in fibroblasts from a subject with homozygous receptor-negative familial hypercholesterolemia. J Lab Clin Med. 1985 Jul;106(1):47–52. [PubMed] [Google Scholar]
- Sodhi H. S., Kudchodkar J., Mason D. T. Cholesterol metabolism in clinical hyperlipidemias. Adv Lipid Res. 1980;17:107–153. doi: 10.1016/b978-0-12-024917-6.50009-4. [DOI] [PubMed] [Google Scholar]
- Tolleshaug H., Goldstein J. L., Schneider W. J., Brown M. S. Posttranslational processing of the LDL receptor and its genetic disruption in familial hypercholesterolemia. Cell. 1982 Oct;30(3):715–724. doi: 10.1016/0092-8674(82)90276-8. [DOI] [PubMed] [Google Scholar]
- Tolleshaug H., Hobgood K. K., Brown M. S., Goldstein J. L. The LDL receptor locus in familial hypercholesterolemia: multiple mutations disrupt transport and processing of a membrane receptor. Cell. 1983 Mar;32(3):941–951. doi: 10.1016/0092-8674(83)90079-x. [DOI] [PubMed] [Google Scholar]

