FREQUENCY-DISTRIBUTIONS OF PLASMA APOLIPOPROTEIN(A) LEVELS AND PHENOTYPES - A COMPARISON BETWEEN SOUTHERN AND NORTHERN CHINESE POPULATIONS

Objective This study was designed to examine the genetic variation and levels of apolipoprotein (a) [apo(a)] in Chinese living in two differ ent geographical regions of China and the influence of the apo(a) size polymorphism on plasma apo(a) levels. Methods An immunoradiometric as say was used to determine plasma apo(a) levels and a simplified and se nsitive SDS-agarose gel electrophoresis method followed by immunoblott ing with chemiluminescent detection for apo(a) phenotyping was employe d to compare the frequency distributions oi apo(a) levels and phenotyp es in southern (Hong Kong) and northern (Henan) Chinese populations. R esults Distributions of plasma apo(a) levels were highly skewed in bot h population groups. Although plasma apo(a) levels were generally high er in northern Chinese than in southern Chinese this was not explained by differences in K-IV repeats allele frequencies between these two p opulation groups. The association of K-IV repeat length with apo(a) le vels is similar in the two populations.Conclusions We conclude that be sides the apo(a) size polymorphism, which is similar in these two Chin ese populations, other factors affect apo(a) levels to a certain degre e. Most likely, this is the sequence variation in apo(a) gene which ma y not be the same in different Chinese populations.