LIPOPROTEIN(A) PHENOTYPES IN JAPANESE CHILDREN - A COHORT STUDY

Background: Elevated serum lipoprotein(a) [Lp(a)] concentrations have been demonstrated to be associated with cardiovascular diseases due to premature atherosclerosis. However, the association of Lp(a) phenotyp es with the development of these diseases remains largely unexplored. Methods: We analyzed the population-based frequencies of serum Lp(a) p henotypes in 269 Japanese children aged 8-13 years in one community. A ccording to the different apolipoprotein(a) [apo(a)] electrophoretic m obilities, Lp(a) was classified into seven single-band and respective double-band phenotypes. Each individual expressed a single (homozygoti c) or a double band (heterozygotic). Results: The serum Lp(a) concentr ation frequency distribution was skewed toward lower levels with a mea n +/- SD of 15.5 +/- 18.0 mg/dl and a median of 11.0 mg/dl. The Lp(a) phenotype frequencies revealed that the frequency of double-band pheno type expression (55%) was higher than that of single bands (44%) and t hat the frequency of phenotypes representative of low molecular weight apo(a) was very low (2%). The mean serum Lp(a) concentration of the d ouble-band-expressing subjects was higher than that of subjects with t he single-band phenotype (20.1 +/- 19.9 vs. 10.5 +/- 15.9 mg/dl, p < 0 .01). Conclusions: These findings of Lp(a) phenotypes in children seem ed to differ from those in Japanese adults in another study; contrary to expectation, the predominant Lp(a) phenotypes found in children wer e those frequently associated with cardiovascular diseases in adults. Thus, it is speculated that children whose Lp(a) phenotypes remain unc hanged during the transition to adulthood may show an increased suscep tibility to cardiovascular disease, although the nutritional effects o n the Lp(a) phenotypes cannot be neglected.