RESUMO
BACKGROUND: Familial hypercholesterolemia is difficult to diagnose because of different expressions of the defective gene in low density lipoprotein (LDL) receptor mutation carriers and the presence of elevated LDL levels in noncarriers. AIM: To study specific biomarkers of atherogenic risk in carriers and noncarriers of low density lipoprotein receptor (LDLR) defective gene and utilize them to screen in molecular biological analysis for defects in the LDL receptor (spot mutation and polymorphism) in severe hypercholesterolemia. PATIENTS AND METHODS: We investigated 120 patients after screening using the Simon-Broome criteria. According to whether there were molecular defects or not, the patients were assigned to two groups--carriers (22 patients, 18.33%) and non-carriers (98 patients, 81.67%). Total cholesterol, triglycerides, HDL cholesterol, apolipoproteins Apo-B and Al were determined using routine methods. LDL-cholesterol was determined by direct methods. ELISA was used in determining the soluble cell adhesion molecules (sICAM-1, sVCAM-1), P-selectine and E-selectine, and high-performance liquid chromatography--total homocysteine. RESULTS: There were no significant differences in gender and anthropometric parameters (P > 0.05) between carriers and non-carriers, but the groups differed significantly in age (P < 0.001). No significant differences were found between the groups in the routine lip profile, the atherogenic lipid index, apolipoproteins B and A1, ADMA, total homocysteine, and the soluble cell adhesion molecules (P > 0.05). We found a statistically significant difference only for the Apo-B/Apo-A1 index in values non standardized by age, which was confirmed after standardization. CONCLUSIONS: Examining all 18 exons of LDLR gene in patients with severe HC we found that 18.33% of them were carriers of mutations and polymorphisms. There was no correlation between the presence of a molecular defect and the routine lipid profile, ADMA, total homocysteine and the soluble cell adhesion molecules; the presence of a molecular defect however, correlated with the Apo-B/Apo-A1 index.