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-codi ng region of the apo(a) gene was studied in 263 patients with severe corona ry heart disease and 97 healthy subjects. Methods: Lp(a) levels were measur ed by ELISA, apo(a) isoform size was determined by SDS-agarose gel electrop horesis, and analysis of the (TTTTA)(n) was carried out by PCR. For statist ical calculation, both groups were divided into low (at least one apo(a) is oform with less than or equal to 22 Kringle IV) and high (both isoforms wit h > 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) TTTT A repeats. Results: Lp(a) levels were higher (P = 0.007), apo(a) isoforms s ize 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 t o be significantly associated with CHD. Conclusion: Nevertheless, these res ults indicate that in CHD patients the (TTTTA)(n) polymorphism has an effec t on Lp(a) levels which is independent of the apo(a) size. (C) 2001 Elsevie r Science B.V. All rights reserved.