Genetic basis of lipoprotein disorders.

Lipoproteins are complexes of lipids and proteins that carry cholesterol in the bloodstream. They are spherical particles with a coat consisting principally of amphiphilic phospho- lipids and proteins, called apolipoproteins, and a core, which is essentially an oil droplet, consisting of varying proportions of triglycerides and cholesteryl esters. Lipoprotein levels are de- termined by genes that code for proteins that control lipopro- tein synthesis, lipoprotein processing, and lipoprotein break- down. These include the apolipoproteins, A-I, A-II, A-IV, B, CI, CII, CIII, D, E, and apo(a), the lipoprotein processing proteins, lipoprotein lipase (LPL),1 hepatic triglyceride lipase (HTGL), lecithin cholesterol acyltransferase (LCAT), and cholesteryl ester transfer protein (CETP), and the lipoprotein receptors, LDL receptor, chylomicron remnant receptor, and scavenger receptor. The following is a brief summary of cur- rent knowledge about the genetic basis of lipoprotein dis- orders. Additional background information and references may be found in several recent review articles (1-1 1).