Heterogeneity of lipoprotein (a): growing complexities.

As new knowledge is being acquired about the highly polymorphic apolipoprotein (a) gene, studies are also being directed at elucidating the factors involved in the synthesis and maturation of apolipoprotein (a) and the determinants controlling the interactions between apolipoprotein (a) and apolipoprotein B100 in lipoprotein (a) assembly. It is now apparent that apolipoprotein (a) is not only size but also sequence polymorphic and that some of the mutations within the lysine-binding site potentially impair the binding of apolipoprotein (a) to lysine-rich domains, such as those in fibrin(ogen) and apolipoprotein B100. At present, there is little knowledge about the effect of the lipoprotein (a) polymorphism on the mechanisms underlying its atherothrombogenic potential. With the current availability of in-vitro, ex-vivo, and transgenic mice models, this issue should be amenable to productive exploration.