title: Subclasses of low-density lipoprotein and very low-density lipoprotein in familial combined hyperlipidemia: relationship to multiple lipoprotein phenotype.
abstract: OBJECTIVE
  The present study addresses the presence of distinct metabolic phenotypes in familial combined hyperlipidemia (FCHL) in relation to small dense low-density lipoprotein (sd LDL) and very low-density lipoprotein (VLDL) subclasses.
  
  
  RESULTS
  Hyperlipidemic FCHL relatives (n=72) were analyzed for LDL size by gradient gel electrophoresis. Pattern B LDL (sd LDL, particle size <258 A) and pattern A LDL (buoyant LDL, particle size > or =258 A) were defined. Analyses showed bimodal distribution of LDL size associated with distinct phenotypes. Subjects with predominantly large, buoyant LDL showed a hypercholesterolemic phenotype and the highest apo B levels. Subjects with predominantly sd LDL showed a hypertriglyceridemic, low high-density lipoprotein (HDL) cholesterol phenotype, with moderately elevated apoB, total cholesterol level, and LDL cholesterol level. Subjects with both buoyant LDL and sd LDL (pattern AB, n=7) showed an intermediate phenotype, with high normal plasma triglycerides. VLDL subfraction analysis showed that the sd LDL phenotype was associated with a 10-times higher number of VLDL1 particles of relatively lower apo AI and apo E content, as well as smaller VLDL2 particles, in combination with increased plasma insulin concentration in comparison to pattern A.
  
  
  CONCLUSIONS
  The present observations underscore the importance of the VLDL triglyceride metabolic pathway in FCHL as an important determinant of the phenotypic heterogeneity of the disorder.
authors.affiliation: Cardiovascular Research Institute Maastricht, Laboratory of Molecular Metabolism and Endocrinology, Department of Medicine, University of Maastricht, The Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: Georgieva
authors.forename: M M J
authors.initials: MM
authors.lastname: van Greevenbroek
authors.forename: R M
authors.initials: RM
authors.lastname: Krauss
authors.forename: M C G J
authors.initials: MC
authors.lastname: Brouwers
authors.forename: V M M-J
authors.initials: VM
authors.lastname: Vermeulen
authors.forename: M G
authors.initials: MG
authors.lastname: Robertus-Teunissen
authors.forename: C J H
authors.initials: CJ
authors.lastname: van der Kallen
authors.forename: T W A
authors.initials: TW
authors.lastname: de Bruin
mesh_terms: D000328:Adult; D016632:Apolipoprotein A-I / Q000097:blood; D001057:Apolipoproteins E / Q000097:blood; D001797:Blood Protein Electrophoresis; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000235:genetics; D006950:Hyperlipidemia, Familial Combined / Q000097:blood* / Q000235:genetics; D006953:Hyperlipoproteinemia Type IV / Q000097:blood / Q000235:genetics; D007328:Insulin / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood / Q000145:classification*; D008079:Lipoproteins, VLDL / Q000097:blood / Q000145:classification*; D008297:Male; D010316:Particle Size; D010641:Phenotype
chemical_list: D016632:Apolipoprotein A-I; D001057:Apolipoproteins E; D007328:Insulin; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL