The association of serum lipoprotein(a) levels, apolipoprotein(a) size and (TTTTA)n polymorphism with coronary heart disease

Background: The association between lipoprotein(a) levels, apolipoprotein(a) size and the (TTTTA)(n) polymorphism which is located in the 5 ' non-coding region of the apo(a) gene was studied in 263 patients with severe coronary heart disease and 97 healthy subjects. Methods: Lp(a) levels were measured by ELISA, apo(a) isoform size was determined by SDS-agarose gel electrophoresis, and analysis of the (TTTTA)(n) was carried out by PCR. For statistical calculation, both groups were divided into low (at least one apo(a) isoform with less than or equal to 22 Kringle IV) and high (both isoforms with > 22 KIV) apo(a) isoform sizes, and into low number (< 10 in both alleles) and high number of (greater than or equal to 10 at least one allele) TTTTA repeats. Results: Lp(a) levels were higher (P = 0.007), apo(a) isoforms size less than or equal to 22 KIV and TTTTA repeats greater than or equal to 10 were more frequent (P = 0.007 and 0.01) in cases than in controls. Lp(a) levels were found to be increased with low apo(a) weight in both groups (both P < 0.0001). In multivariate logistic regression analysis, only the Lp(a) levels (P = 0.005) and (TTTTA)(n) polymorphism (P = 0.002) were found to be significantly associated with CHD. Conclusion: Nevertheless, these results indicate that in CHD patients the (TTTTA)(n) polymorphism has an effect on Lp(a) levels which is independent of the apo(a) size. (C) 2001 Elsevier Science B.V. All rights reserved.