Aim: Familial Hypercholesterolemia (FH) patients have an increased cardiovascular risk due to high TC or LDL-C levels. Lp(a) chemical structure is similar to LDL and elevated Lp(a) is considered an independent risk factor for cardiovascular disease (CVD). Recently, it has been described that in patients with high Lp(a), the Lp(a)-C can contribute up to 25% to 50% of all LDL-C. In the present work we aim to determine if elevated Lp(a) concentrations can contribute to clinical phenotype of FH.
Methods: A cohort of 1374 individuals (875 adults and 499 children) with clinical diagnosis of FH was analysed, including lipid profile (automatic biochemical equipment) and molecular study of LDLR, APOB and PCSK9 (PCR and Sanger sequencing). Data was analysed by SPSS using Mann-Whitney and Qui-square tests.
Results: The cohort was divided according to the genetic diagnosis: children (283 FH-positive; 216 FH-negative); adults (538 FH-positive; 337 FH-negative). In children, Lp(a) mean levels were statistically significant higher in FH-negative when compared with FH-positive (59.9mg/dL vs 41.2mg/dL, p<0.001). 33.1% of children present Lp(a)>50mg/dL, of these 56.3% are FH-negative vs 43.7% FH-positive (p<0.001). In adults, Lp(a) mean levels were higher in FH-negative but not statistically significant (55.9mg/dL vs 52.7mg/dL); 15.8% of adults present a premature CVD (mean age 46.3). In the group of adults with Lp(a)<50mg/dL 12% present pCVD, while 22% present pCVD in the group of adults with Lp(a)>50mg/dL (p<0.001.
Conclusions: Almost 50% of these FH mutation negative children have Lp(a)>50 mg/dL that can be contributing to elevated LDL-C levels resulting in a FH-like phenotype. Most probably in these cases the genetic cause of their hypercholesterolaemia is not FH but hyper Lp(a). We’ve also observed that in the group of adults 37% present an elevated Lp(a), that is an additional risk factor to their hypercholesterolemia. Since LDL-C levels of patients with elevated Lp(a) cannot be reduced if the Lp(a) remains elevated, specific therapies to lower Lp(a) are necessary in these patients.

02 - HIGH LIPOPROTEIN(A) CHOLESTEROL IN PATIENTS WITH FAMILIAL HYPERCHOLESTEROLEMIA