Background: Apolipoprotein E (ApoE) plays a role in the regulation of lipid metabolism in humans. ApoE, a 229-amino-acid polypeptide, is classified into three major isoforms (E2, E3, and E4) according to the differences in amino acids at positions 112 and 158. In the normal population, ApoE3 isoform is the most prevalent, and ApoE2 or E4 is frequently associated with hyperlipoproteinemia. The objective of this work was to investigate the relationship between ApoE gene polymorphism and coronary heart disease (CHD) in Gaza Strip and investigate the association between serum lipid levels and CHD. Material and Methods: The study population consisted of 137 subjects including 69 CHD cases (45 male, 24 female) and 68 healthy subjects (33 male and 35 female). Results: The ApoE3/E3 genotype was the most common in the control and the CHD groups. ApoE2/E3 and ApoE3/E4 were the next most common genotypes. The frequencies of ApoE alleles in the CHD subjects were 0.826 for E3, 0.137 for E4, and 0.0362 for E2. These frequencies are comparable to those found in the control group which were 0.875 for the E3, 0.073 for E4, and 0.0515 for E2. No statistically significant differences in ApoE genotypes were found between the patients and the control groups. Moreover, there was no significant difference between the mean of triglyceride (TG) and HDL levels among different ApoE genotypes. However, there was a significant difference in the mean of LDL and ApoE genotypes where the mean of LDL was 218.17 mg/dl in ApoE4, 149.67 mg/dl in ApoE2, and 184.52 mg/dl in ApoE3. A significant difference was also evident between the mean of LDL levels in the CHD and the control group where the mean of LDL was 126 mg/dl in CHD and 111.47 mg/dl in the control group. Our study indicated that there was no significant difference between the mean of cholesterol and TG levels of the CHD and the control groups. Conclusions: To our knowledge, this is the first study in Gaza Strip investigating the relation between ApoE genotypes and CHD. Further investigations are needed to link other genetic factors to CHD.
Key words: Apolipoprotien E, Polymerase chain reaction- restriction fragment length polymorphism, coronary heart disease, gene polymorphism.