Background. High plasma cholesterol is one of the risk factors of atherosclerosis. Both environmental (diet, physic activity) and genetic factors have been concerned in the development of hypercholesterolemia. Cholesterol 7α hydroxylase (CYP-7A1) is a key enzyme in the bile acid synthesis and it plays an important role in cholesterol catabolism. The aim of the study was to establish the role of A–204 → C polymorphism in CYP-7A1 gene in plasma lipid determination in children. Methods and Results. Using PCR and restriction analysis (BsaI) we have measured A–204→C polymorphism in CYP-7A1 gene in two groups of children selected from opposite ends of the cholesterol distribution curve of 2000 children. Eighty-two children in high- (HCG) and eighty-six children in low- (LCG) cholesterolemic groups participated in the study. No significant difference was found in the frequencies of the genotypes or alleles of the A–204→C polymorphism in the CYP-7A1 gene between HCG and LCG. In HCG, C/C-204 homozygotes have the highest and A/A homozygotes the lowest levels of LDL-cholesterol (4,21±0,68 mmol/l vers. 3,69±0,60 mmol/l, p<0.05). No associations between lipid parameters and genotypes within the LCG group were found. Conclusions. The A–204→ C polymorphism in the gene for CYP-7A1 is not the major determinant of plasma lipid levels in childhood. Its impact is expressed only on high cholesterol background.

        Key words: cholesterol 7α hydroxylase, lipids, polymorphism.