Objective: Lipoprotein (a) (Lp(a)) is a modified LDL particle in human plasma. Elevated Lp(a) plasma concentration has been associated with increase risk of premature heart disease in most cross-sectional studies. Familial hypercholesterolemia (FH) is a genetic disorder characterized by an elevation of LDL cholesterol (LDL-C) caused by molecular defects in the LDL receptor gene. The aim of our study is to analyze Lp(a) values in a genetic diagnosed FH group without coronary heart disease (CHD) and explain the considerable variation in clinical severity of FH patients.
Method: We have study plasma lipids and lipoprotein levels in 60 subjects with familial hypercholesterolemia without CHD and in 74 normolipidemic controls without personal history of CHD and dyslipidemia of the Valencia area in Spain.
Results: We found differences in total and LDL cholesterol levels and apo B values as expected and also in plasma Lp(a) levels and log transformed values between FH subjects and normolipidemic controls (22.3 mg/dl +/- 19.4 vs 12.5 mg/dl +/- 12.6 p = 0.001 and 1.12 +/- 0.53 vs. 0.84 +/- 0.58 p = 0.008). The percentage of FH subjects with a cut point Lp(a) value > 20 mg/dl is significantly elevated in this group (47% vs 21% p = 0.002). Because of family relationships within the entire study population we also have compared 23 FH probands with the normolipidemic controls. Again the same results have been obtained (Lp(a) levels of 23.21 mg/dl +/- 19.2 vs 12.54 mg/dl +/- 12.63 p = 0.019 and log Lp(a) values of 1.19 +/- 0.42 vs 0.84 +/- 0.58 p = 0.01).
Conclusion: Our results indicate that FH subjects will have a more cardiovascular risk due to the potentiation of hypercholesterolemia and elevated Lp(a) values, indicating the addition effects of two different locus implicated in premature coronary heart disease and could explain the considerable variation in clinical severity of FH.