Association between Ava II Polymorphism in LDL Receptor Gene and Hyperlipidemic Ischemic Stroke Patients

Abstract

Increased plasma level of low density lipoprotein-cholesterol (LDL-C) is a risk factor for atherosclerosis development and severity. The low-density lipoprotein receptor (LDL-R) is one of the control mechanisms that the liver uses for cholesterol homeostasis. Gene variations in the LDL-R have been reported to cause hypercholesterolemia and consequently lead to cardiovascular diseases (CVD). The study investigates the association between polymorphism of the LDL-R gene and plasma lipid parameters levels in patients with ischemic stroke. 115 controls and 95 ischemic stroke patients matched for sex and age were enrolled in the study. Lipid profiles were measured using biochemical standards methods and lipoprotein ratios were calculated. Ava II (rs5925) genotypes were performed by PCR-RFLP combined with 2% gel electrophoresis. The frequencies of A-A-, A-A+ and A+A+ genotypes for LDL-R gene polymorphism were 73.04%, 23.48% and 3.48% for the control, 18.95%, 72.63% and 8.42% for the ischemic stroke subjects (P<0.0001) respectively. The frequencies of A- and A+ alleles were 84.78% and 15.22% for the control and 55.26% and 44.74% for the stroke subjects (P<0.0001) respectively. The study shows that the mutant allele of the LDL-R gene was associated with dyslipidemia for both subjects. The subjects with A-A- genotype had significant (P=0.0001-0.0063) lower plasma levels of TC, TG, LDL-C, VLDL-C, Non-HDL-C, TC/HDL-C, TG/HDL-C, LDL-C/HDL-C, AIP and AC than the subjects with A-A+ and A+A+ genotypes for both subjects. The effect of LDL-R gene Ava Ⅱ polymorphism on plasma lipid levels is associated with higher lipid parameters for both subjects.