Lipoprotein (a), Lp (a), is a spherical particle which floats at densities 1.05-1.1 g/ml. Lp(a) can be defined as a family of particles that contain apo B100 and highly glycosylated apo (a). Lp (a) is an independent risk factor for the development of coronary heart disease. High levels of Lp(a) are associated with premature myocardial infarction and cerebrovascular disease. The pathogenicity of Lp(a) may be due to its cholesteryl ester content contributing to the formation of foam cells. Apo (a) varies in size among individuals owing to different number of cystein-rich sequences that are homologous to kringle 4 of plasminogen. The size of the apo (a) gene correlates directly with the size of the apo (a) protein and inversely with the concentration of Lp(a) in plasma.